V. SALMONIDÆ—(Continued)
=SALMO, the Trout and Atlantic Salmon.=—The genus Salmo comprises those forms of salmon which have been longest known. As in related genera, the mouth is large, and the jaws, palatines, and tongue are armed with strong teeth. The vomer is flat, its shaft not depressed below the level of the head or chevron (the anterior end). There are a few teeth on the chevron; and behind it, on the shaft, there is either a double series of teeth or an irregular single series. These teeth in the true salmon disappear with age, but in the others (the black-spotted trout) they are persistent. The scales are silvery and moderate or small in size. There are 9 to 11 developed rays in the anal fin. The caudal fin is truncate, or variously concave or forked. There are usually 40 to 70 pyloric cœca, 11 or 12 branchiostegals, and about 20 (8 + 12) gill-rakers. The sexual peculiarities are in general less marked than in Oncorhynchus; they are also greater in the anadromous species than in those which inhabit fresh waters. In general the male in the breeding season is redder, its jaws are prolonged, the front teeth enlarged, the lower jaw turned upwards at the end, and the upper jaw notched, or sometimes even perforated, by the tip of the lower. All the species of Salmo (like those of Oncorhynchus) are more or less spotted with black. Unlike the species of Oncorhynchus, the species of Salmo feed more or less while in fresh water, and the individuals for the most part do not die after spawning, although many old males do thus perish.
=The Atlantic Salmon.=—The large species of Salmo, called salmon by English-speaking people (Salmo salar, Salmo trutta), are marine and anadromous, taking the place in the North Atlantic occupied in the North Pacific by the species of Oncorhynchus. Two others more or less similar in character occur in Japan and Kamchatka. The others (trout), forming the subgenus Salar, are non-migratory, or at least irregularly or imperfectly anadromous. The true or black-spotted trout abound in all streams of northern Europe, northern Asia, and in that part of North America which lies west of the Mississippi Valley. The black-spotted trout are entirely wanting in eastern America—a remarkable fact in geographical distribution, perhaps explained only on the hypothesis of the comparatively recent and Eurasiatic origin of the group, which, we may suppose, has not yet had opportunity to extend its range across the plains, unsuitable for salmon life, which separate the upper Missouri from the Great Lakes.
The salmon (Salmo salar) is the only black-spotted salmonoid found in American waters tributary to the Atlantic. In Europe, where other species similarly colored occur, the species may be best distinguished by the fact that the teeth on the shaft of the vomer mostly disappear with age. From the only other species positively known, the salmon trout (Salmo trutta), which shares this character, the true salmon may be distinguished by the presence of but eleven scales between the adipose fin and the lateral line, while Salmo trutta has about fourteen. The scales are comparatively large in the salmon, there being about one hundred and twenty-five in the lateral line. The caudal fin, which is forked in the young, becomes, as in other species of salmon, more or less truncate with age. The pyloric cœca are fifty to sixty in number.
The color in adults, according to Dr. Day, is "superiorly of a steel-blue, becoming lighter on the sides and beneath. Mostly a few rounded or X-shaped spots scattered above the lateral line and upper half of the head, being more numerous in the female than in the male. Dorsal, caudal, and pectoral fins dusky; ventrals and anal white, the former grayish internally. Prior to entering fresh waters these fish are of a brilliant steel-blue along the back, which becomes changed to a muddy tinge when they enter rivers. After these fish have passed into the fresh waters for the purpose of breeding, numerous orange streaks appear in the cheeks of the male, and also spots or even marks of the same, and likewise of a red color, on the body. It is now termed a 'redfish.' The female, however, is dark in color and known as 'blackfish.' 'Smolts' (young river fish) are bluish along the upper half of the body, silvery along the sides, due to a layer of silvery scales being formed over the trout-like colors, while they have darker fins than the yearling 'ping,' but similar bands and spots, which can be seen (as in the parr) if the example be held in certain positions of light. 'Parr' (fishes of the year) have two or three black spots only on the opercle, and black spots and also orange ones along the upper half of the body, and no dark ones below the lateral line, although there may be orange ones which can be seen in its course. Along the side of the body are a series (12 to 15) of transverse bluish bands, wider than the ground color and crossing the lateral line, while in the upper half of the body the darker color of the back forms an arch over each of these bands, a row of spots along the middle of the rayed dorsal fin, and the adipose orange-tipped."
The dusky cross-shades found in the young salmon or parr are characteristic of the young of salmon, trout, grayling, and nearly all the other Salmonidæ.
The salmon of the Atlantic is, as already stated, an anadromous fish, spending most of its life in the sea, and entering the streams in the fall for the purpose of reproduction. The time of running varies much in different streams and also in different countries. As with the Pacific species, these salmon are not easily discouraged in their progress, leaping cascades and other obstructions, or, if these prove impassable, dying after repeated fruitless attempts.
The young salmon, known as the "parr," is hatched in the spring. It usually remains about two years in the rivers, descending at about the third spring to the sea, when it is known as "smolt." In the sea it grows much more rapidly, and becomes more silvery in color, and is known as "grilse." The grilse rapidly develop into the adult salmon; and some of them, as in the case with the grilse of the Pacific salmon, are capable of reproduction.
After spawning the salmon are very lean and unwholesome in appearance, as in fact. They are then known as "kelts." The Atlantic salmon does not ascend rivers to any such distances as those traversed by the quinnat and the blue-back. Its kelts, therefore, for the most part survive the act of spawning. Dr. Day thinks that they feed upon the young salmon in the rivers, and that, therefore, the destruction of the kelts might increase the supply of salmon.
As a food-fish the Atlantic salmon is very similar to the quinnat salmon, neither better nor worse, so far as I can see, when equally fresh. In both the flesh is rich and finely flavored; but the appetite of man becomes cloyed with salmon-flesh sooner than with that of whitefish, smelt, or charr. In size the Atlantic salmon does not fall far short of the quinnat. The average weight of the adult is probably less than fifteen pounds. The largest one of which I find a record was taken on the coast of Ireland in 1881, and weighed 84¾ pounds.
The salmon is found in Europe between the latitude of 45° and 75°. In the United States it is now rarely seen south of Cape Cod, although formerly the Hudson and numerous other rivers were salmon-streams. Overfishing, obstructions in the rivers, and pollution of the water by manufactories and by city sewage are agencies against which the salmon cannot cope.
Seven species of salmon (as distinguished from trout) are recognized by Dr. Günther in Europe, and three in America. The landlocked forms, abundant in Norway, Sweden, and Maine, which cannot, or at least do not, descend to the sea, are regarded by him as distinct species. "The question," observes Dr Günther, "whether any of the migratory species can be retained by artificial means in fresh water, and finally accommodate themselves to a permanent sojourn therein, must be negatived for the present." On this point I think that the balance of evidence leads to a different conclusion. These fresh-water forms (Sebago and Ouananiche) are actually salmon which have become landlocked. I have compared numerous specimens of the common landlocked salmon (Salmo salar sebago) of the lakes of Maine and New Brunswick with landlocked salmon (Salmo salar hardini) from the lakes of Sweden, and with numerous migratory salmon, both from America and Europe. I see no reason for regarding them as specifically distinct. The differences are very trivial in kind, and not greater than would be expected on the hypothesis of recent adaptation of the salmon to lake life. We have therefore on our Atlantic coast but one species of salmon, Salmo salar. The landlocked form of the lakes of Maine is Salmo salar sebago. The Ouananiche of Lake St. John and the Saguenay, beloved of anglers, is Salmo salar ouananiche.
=The Ouananiche.=—Dr. Henry Van Dyke writes thus of the Ouananiche: "But the prince of the pool was the fighting Ouananiche, the little salmon of St. John. Here let me chant thy praise, thou noblest and most high-minded fish, the cleanest feeder, the merriest liver, the loftiest leaper, and the bravest warrior of all creatures that swim! Thy cousin, the trout, in his purple and gold with crimson spots, wears a more splendid armor than thy russet and silver mottled with black, but thine is the kinglier nature.
"The old salmon of the sea who begat thee long ago in these inland waters became a backslider, descending again to the ocean, and grew gross and heavy with coarse feeding. But thou, unsalted salmon of the foaming floods, not landlocked as men call thee, but choosing of thine own free will to dwell on a loftier level in the pure, swift current of a living stream, hath grown in grace and risen to a better life.
"Thou art not to be measured by quantity but by quality, and thy five pounds of pure vigor will outweigh a score of pounds of flesh less vitalized by spirit. Thou feedest on the flies of the air, and thy food is transformed into an aerial passion for flight, as thou springest across the pool, vaulting toward the sky. Thine eyes have grown large and keen by piercing through the foam, and the feathered hook that can deceive thee must be deftly tied and delicately cast. Thy tail and fins, by ceaseless conflict with the rapids, have broadened and strengthened, so that they can flash thy slender body like a living arrow up the fall. As Launcelot among the knights, so art thou among the fish, the plain-armored hero, the sunburnt champion of all the water-folk."
Dr. Francis Day, who has very thoroughly studied these fishes, takes, in his memoir on "The Fishes of Great Britain and Ireland," and in other papers, a similar view in regard to the European species. Omitting the species with permanent teeth on the shaft of the vomer (subgenus Salar), he finds among the salmon proper only two species, Salmo salar and Salmo trutta. The latter species, the sea-trout or salmon-trout of England and the estuaries of northern Europe, is similar to the salmon in many respects, but has rather smaller scales, there being fourteen in an oblique series between the adipose fin and the lateral line. It is not so strong a fish as the salmon, nor does it reach so large a size. Although naturally anadromous, like the true salmon, landlocked forms of the salmon-trout are not uncommon. These have been usually regarded as different species, while aberrant or intermediate individuals are usually regarded as hybrids. The salmon-trout of Europe have many analogies with the steelhead of the Pacific.
The present writer has examined many thousands of American Salmonidæ, both of Oncorhynchus and Salmo. While many variations have come to his attention, and he has been compelled more than once to modify his views as to specific distinctions, he has never yet seen an individual which he had the slightest reason to regard as a "hybrid." It is certainly illogical to conclude that every specimen which does not correspond to our closet-formed definition of its species must therefore be a "hybrid" with some other. There is no evidence worth mentioning, known to me, of extensive hybridization in a state of nature in any group of fishes. This matter is much in need of further study; for what is true of the species in one region, in this regard, may not be true of others. Dr. Günther observes:
"Johnson, a correspondent of Willughby, had already expressed his belief that the different salmonoids interbreed; and this view has since been shared by many who have observed these fishes in nature. Hybrids between the sewin (Salmo trutta cambricus) and the river-trout (Salmo fario) were numerous in the Rhymney and other rivers of South Wales before salmonoids were almost exterminated by the pollutions allowed to pass into these streams, and so variable in their characters that the passage from one species to the other could be demonstrated in an almost unbroken series, which might induce some naturalists to regard both species as identical. Abundant evidence of a similar character has accumulated, showing the frequent occurrence of hybrids between Salmo fario and S. trutta.... In some rivers the conditions appear to be more favorable to hybridism than in others in which hybrids are of comparatively rare occurrence. Hybrids between the salmon and other species are very scarce everywhere."
Very similar to the European Salmo trutta is the trout of Japan (Salmo perryi), the young called yamabe, the adult kawamasu, or river-salmon. This species abounds everywhere in Japan, the young being the common trout of the brooks, black-spotted and crossed by parr-marks, the adult reaching a weight of ten or twelve pounds in the larger rivers and descending to the sea. In Kamchatka is another large, black-spotted, salmon-like species properly to be called a salmon-trout. This is Salmo mykiss, a name very wrongly applied to the cutthroat trout of the Columbia.
The black-spotted trout, forming the subgenus Salar, differ from Salmo salar and Salmo trutta in the greater development of the vomerine teeth, which are persistent throughout life, in a long double series on the shaft of the vomer. About seven species are laboriously distinguished by Dr. Günther in the waters of western Europe. Most of these are regarded by Dr. Day as varieties of Salmo fario. The latter species, the common river-trout or lake-trout of Europe, is found throughout northern and central Europe, wherever suitable waters occur. It is abundant, gamy, takes the hook readily, and is excellent as food. It is more hardy than the different species of charr, although from an æsthetic point of view it must be regarded as inferior to all of the Salvelini. The largest river-trout recorded by Dr. Day weighed twenty-one pounds. Such large individuals are usually found in lakes in the north, well stocked with smaller fishes on which trout may feed. Farther south, where the surroundings are less favorable to trout-life, they become mature at a length of less than a foot, and a weight of a few ounces. These excessive variations in the size of individuals have received too little notice from students of Salmonidæ. Similar variations occur in all the non-migratory species of Salmo and of Salvelinus. Numerous river-trout have been recorded from northern Asia, but as yet nothing can be definitely stated as to the number of species actually existing.
=The Black-spotted Trout.=—In North America only the region west of the Mississippi Valley, the streams of southeastern Alaska, and the valley of Mackenzie River have species of black-spotted trout. There are few of these north of Sitka in Alaska, although black-spotted trout are occasionally taken on Kadiak and about Bristol Bay, and none east of the Rocky Mountain region. If we are to follow the usage of the names "salmon" and "trout" which prevails in England, we should say that, in America, it is only these western regions which have any trout at all. Of the number of species (about twenty-five in all) which have been indicated by authors, certainly not more than about 8 to 10 can possibly be regarded as distinct species. The other names are either useless synonyms, or else they have been applied to local varieties which pass by degrees into the ordinary types.
=The Trout of Western America.=—In the western part of America are found more than a score of forms of trout of the genus Salmo, all closely related and difficult to distinguish. There are representatives in the head-waters of the Rio Grande, Arkansas, South Platte, Missouri, and Colorado rivers; also in the Great Salt Lake basin, throughout the Columbia basin, in all suitable waters from southern California and Chihuahua to Sitka, and even to Bristol Bay, similar forms again appearing in Kamchatka and Japan.
Among the various more or less tangible species that may be recognized, three distinct series appear. These have been termed the cutthroat-trout series (allies of Salmo clarkii), the rainbow-trout series (allies of Salmo irideus), and the steelhead series (allies of Salmo rivularis, a species more usually but wrongly called Salmo gairdneri).
The steelhead, or rivularis series, is found in the coastwise streams of California and in the streams of Oregon and Washington, below the great Shoshone Falls of Snake River, and northward in Alaska along the mainland as far as Skaguay. The steelhead-trout reach a large size (10 to 20 pounds). They spend a large part of their life in the sea. In all the true steelheads the head is relatively very short, its length being contained about five times in the distance from tip of snout to base of caudal fin. The scales in the steelhead are always rather small, about 150 in a linear series, and there is no red under the throat. The spots on the dorsal fin are fewer in the steelhead (4 to 6 rows) than in the other American trout.
The rainbow forms are chiefly confined to the streams of California and Oregon. In these the scales are large (about 135 in a lengthwise series) and the head is relatively large, forming nearly one-fourth of the length to base of caudal. These enter the sea only when in the small coastwise streams. Usually they have no red under the throat. The cutthroat forms are found from Humboldt Bay northward as far as Sitka, in the coastwise streams of northern California, Oregon, Washington, and Alaska, and all the clear streams on both sides of the Rocky Mountains, and in the Great Basin and the head-waters of the Colorado. The cutthroat-trout have the scales small, about 180, and there is always a bright dash of orange-red on each side concealed beneath the branches of the lower jaw. Along the western slope of the Sierra Nevada there are also forms of trout with the general appearance of rainbow-trout and evidently belonging to that species, but with scales intermediate in number (in McCloud River), var. shasta, or with scales as small as in the typical cutthroat (Kern River), var. gilberti. In these small-scaled forms more or less red appears below the lower jaw, and they are doubtless what they appear to be, really intermediate between clarkii and irideus, although certainly nearest the latter. A similar series of forms occurs in the Columbia basin, the upper Snake being inhabited by clarkii and the lower Snake by clarkii and rivularis, together with a medley of forms apparently intermediate.
It seems probable that the American trout originated in Asia, extended its range to southeast Alaska, thence southward to the Fraser and Columbia, thence to the Yellowstone and the Missouri via Two-Ocean Pass; from the Snake River to the Great Basins of Utah and Nevada; from the Missouri southward to the Platte and the Arkansas, thence from the Platte to the Rio Grande and the Colorado, and then from Oregon southward coastwise and along the Sierras to northern Mexico, thence northward and coastwise, the sea-running forms passing from stream to stream.
Of the American species the rainbow trout of California (Salmo irideus) most nearly approaches the European Salmo fario. It has the scales comparatively large, although rather smaller than in Salmo fario, the usual number in a longitudinal series being about 135. The mouth is smaller than in other American trout; the maxillary, except in old males, rarely extending beyond the eye. The caudal fin is well forked, becoming in very old fishes more nearly truncate. The head is relatively large, about four times in the total length. The size of the head forms the best distinctive character. The color, as in all the other species, is bluish, the sides silvery in the males, with a red lateral band, and reddish and dusky blotches. The head, back, and upper fins are sprinkled with round black spots, which are very variable in number, those on the dorsal usually in about nine rows. In specimens taken in the sea this species, like most other trout in similar conditions, is bright silvery, and sometimes immaculate. This species is especially characteristic of the waters of California. It abounds in every clear brook, from the Mexican line northward to Mount Shasta, or beyond, the species passing in the Columbia region by degrees into the species or form known as Salmo masoni, the Oregon rainbow trout, a small rainbow trout common in the forest streams of Oregon, with smaller mouth and fewer spots on the dorsal. No true rainbow trout have been anywhere obtained to the eastward of the Cascade Range or of the Sierra Nevada, except as artificially planted in the Truckee River. The species varies much in size; specimens from northern California often reach a weight of six pounds, while in the streams above Tia Juana in Lower California the southernmost locality from which I have obtained trout, they seldom exceed a length of six inches. Although not usually an anadromous species, the rainbow trout frequently moves about in the rivers, and it often enters the sea, large sea-run specimens being often taken for steelheads. Several attempts have been made to introduce it in Eastern streams, but it appears to seek the sea when it is lost. It is apparently more hardy and less greedy than the American charr, or brook-trout (Salvelinus fontinalis). On the other hand, it is distinctly inferior to the latter in beauty and in gaminess.
Three varieties of some importance have been indicated, Salmo irideus stonei, the Nissui trout of the Klamath, with spots on the posterior parts only, Salmo irideus shasta of the upper Sacramento, and the small-scaled Salmo irideus gilberti of the Kings and Kern rivers. In the head-waters of the Kern, in a stream called Volcano Creek or Whitney Creek, the waterfall sometimes called Agua-Bonita shuts off the movements of the trout. Above this fall is a dwarf form with bright golden fins, and the scales scarcely imbricated. This is the "golden trout of Mount Whitney," Salmo irideus agua-bonita. It will possibly be found to change back to the original type if propagated in different waters.
In beauty of color, gracefulness of form and movement, sprightliness when in the water, reckless dash with which it springs from the water to meet the descending fly ere it strikes the surface, and the mad and repeated leaps from the water when hooked, the rainbow trout must ever hold a very high rank. "The gamest fish we have ever seen," writes Dr. Evermann, "was a 16-inch rainbow taken on a fly in a small spring branch tributary of Williamson River in southern Oregon. It was in a broad and deep pool of exceedingly clear water. As the angler from behind a clump of willows made the cast the trout bounded from the water and met the fly in the air a foot or more above the surface; missing it, he dropped upon the water, only to turn about and strike viciously a second time at the fly just as it touched the surface; though he again missed the fly, the hook caught him in the lower jaw from the outside, and then began a fight which would delight the heart of any angler. His first effort was to reach the bottom of the pool, then, doubling upon the line, he made three jumps from the water in quick succession, clearing the surface in each instance from one to four feet, and every time doing his utmost to free himself from the hook by shaking his head as vigorously as a dog shakes a rat. Then he would rush wildly about in the large pool, now attempting to go down over the riffle below the pool, now trying the opposite direction, and often striving to hide under one or the other of the banks. It was easy to handle the fish when the dash was made up or down stream or for the opposite side, but when he turned about and made a rush for the protection of the overhanging bank upon which the angler stood it was not easy to keep the line taut. Movements such as these were frequently repeated, and two more leaps were made. But finally he was worn out after as honest a fight as trout ever made."
"The rainbow takes the fly so readily that there is no reason for resorting to grasshoppers, salmon-eggs, or other bait. It is a fish whose gaminess will satisfy the most exacting of expert anglers and whose readiness to take any proper line will please the most impatient of inexperienced amateurs."
The steelhead (Salmo rivularis) is a large trout, reaching twelve to twenty pounds in weight, found abundantly in river estuaries and sometimes in lakes from Lynn Canal to Santa Barbara. The spent fish abound in the rivers in spring at the time of the salmon-run. The species is rarely canned, but is valued for shipment in cold storage. Its bones are much more firm than those of the salmon—a trait unfavorable for canning purposes. The flesh when not spent after spawning is excellent. The steelhead does not die after spawning, as all the Pacific salmon do.
It is thought by some anglers that the young fish hatched in the brooks from eggs of the steelhead remain in mountain streams from six to thirty-six months, going down to the sea with the high waters of spring, after which they return to spawn as typical steelhead trout. I now regard this view as unfounded. In my experience the rainbow and the steelhead are always distinguishable: the steelhead abounds where the rainbow trout is unknown; the scales in the steelhead are always smaller (about 155) than in typical rainbow trout; finally, the small size of the head in the steelhead is always distinctive.
The Kamloops trout, described by the writer from the upper Columbia, seems to be a typical steelhead as found well up the rivers away from the sea. Derived from the steelhead, but apparently quite distinct from it, are three very noble trout, all confined so far as yet known to Lake Crescent in northwestern Washington. These are the crescent trout, Salmo crescentis, the Beardslee trout, Salmo beardsleei, and the long-headed trout, Salmo bathæcetor. The first two, discovered by Admiral L. A. Beardslee, are trout of peculiar attractiveness and excellence. The third is a deep-water form, never rising to the surface, and caught only on set lines. Its origin is still uncertain, and it may be derived from some type other than the steelhead.
=Cutthroat or Red-throated Trout.=—This species has much smaller scales than the rainbow trout or steelhead, the usual number in a longitudinal series being 160 to 170. Its head is longer (about four times in length to base of caudal). Its mouth is proportionately larger, and there is always a narrow band of small teeth on the hyoid bone at the base of the tongue. These teeth are always wanting in Salmo irideus and rivularis in which species the rim of the tongue only has teeth. The color in Salmo clarkii is, as in other species, exceedingly variable. In life there is always a deep-red blotch on the throat, between the branches of the lower jaw and the membrane connecting them. This is not found in other species, or is reduced to a narrow strip or pinkish shade. It seems to be constant in all varieties of Salmo clarkii, at all ages, thus furnishing a good distinctive character. It is the sign manual of the Sioux Indians, and the anglers have already accepted from this mark the name of cutthroat-trout. The cutthroat-trout of some species is found in every suitable river and lake in the great basin of Utah, in the streams of Colorado, Wyoming, and Montana, on both sides of the Rocky Mountains. It is also found throughout Oregon, Washington, Idaho, British Columbia, the coastwise islands of southeastern Alaska (Baranof, etc.), to Kadiak and Bristol Bay, probably no stream or lake suitable for trout-life being without it. In California the species seems to be comparatively rare, and its range rarely extending south of Cape Mendocino. Large sea-run individuals analogous to the steelheads are sometimes found in the mouth of the Sacramento. In Washington and Alaska this species regularly enters the sea. In Puget Sound it is a common fish. These sea-run individuals are more silvery and less spotted than those found in the mountain streams and lakes. The size of Salmo clarkii is subject to much variation. Ordinarily four to six pounds is a large size; but in certain favored waters, as Lake Tahoe, and the fjords of southeastern Alaska, specimens from twenty to thirty pounds are occasionally taken.
Those species or individuals dwelling in lakes of considerable size, where the water is of such temperature and depth as insures an ample food-supply, will reach a large size, while those in a restricted environment, where both the water and food are limited, will be small directly in proportion to these environing restrictions. The trout of the Klamath Lakes, for example, reach a weight of at least 17 pounds, while in Fish Lake in Idaho mature trout do not exceed 8 to 9¼ inches in total length or one-fourth pound in weight. In small creeks in the Sawtooth Mountains and elsewhere they reach maturity at a length of 5 or 6 inches, and are often spoken of as brook-trout and with the impression that they are a species different from the larger ones found in the lakes and larger streams. But as all sorts and gradations between these extreme forms may be found in the intervening and connecting waters, the differences are not even of sub-specific significance.
Dr. Evermann observes: "The various forms of cutthroat-trout vary greatly in game qualities; even the same subspecies in different waters, in different parts of its habitat, or at different seasons, will vary greatly in this regard. In general, however, it is perhaps a fair statement to say that the cutthroat-trout are regarded by anglers as being inferior in gaminess to the Eastern brook-trout. But while this is true, it must not by any means be inferred that it is without game qualities, for it is really a fish which possesses those qualities in a very high degree. Its vigor and voraciousness are determined largely, of course, by the character of the stream or lake in which it lives. The individuals which dwell in cold streams about cascades and seething rapids will show marvelous strength and will make a fight which is rarely equaled by its Eastern cousin; while in warmer and larger streams and lakes they may be very sluggish and show but little fight. Yet this is by no means always true. In the Klamath Lakes, where the trout grow very large and where they are often very logy, one is occasionally hooked which tries to the utmost the skill of the angler to prevent his tackle from being smashed and at the same time save the fish."
Of the various forms derived from Salmo clarkii some mere varieties, some distinct species, the following are among the most marked:
Salmo henshawi, the trout of Lake Tahoe and its tributaries and outlet, Truckee River, found in fact also in the Humboldt and the Carson and throughout the basin of the former glacial lake called Lake Lahontan. This is a distinct species from Salmo clarkii and must be regarded as the finest of all the cutthroat-trout. It is readily known by its spotted belly, the black spots being evenly scattered over the whole surface of the body, above and below. This is an excellent game-fish, and from Lake Tahoe and Pyramid Lake it is brought in large numbers to the markets of San Francisco. In the depths of Lake Tahoe, which is the finest mountain lake of the Sierra Nevada, occurs a very large variety which spawns in the lake, Salmo henshawi tahoensis. This reaches a weight of twenty-eight pounds.
In the Great Basin of Utah is found a fine trout, very close to the ordinary cutthroat of the Columbia, from which it is derived. This is known as Salmo clarkii virginalis. In Utah Lake it reaches a large size.
In Waha Lake in Washington, a lake without outlet, is found a small trout with peculiar markings called Salmo clarkii bouvieri.
In the head-waters of the Platte and Arkansas rivers is the small green-back trout, green or brown, with red throat-patch and large black spots. This is Salmo clarkii stomias, and it is especially fine in St. Vrain's River and the streams of Estes Park. In Twin Lakes, a pair of glacial lakes tributary of the Arkansas near Leadville, is found Salmo clarkii macdonaldi, the yellow-finned trout, a large and very handsome species living in deep water, and with the fins golden yellow. This approaches the Colorado trout, Salmo clarkii pleuriticus, and it may be derived from the latter, although it occurs in the same waters as the very different green-back trout, or Salmo clarkii stomias.
Two fine trout derived from Salmo clarkii have been lately discovered by Dr. Daniel G. Elliot in Lake Southerland, a mountain lake near Lake Crescent, but not connected with it, the two separated from the sea by high waterfalls. These have been described by Dr. Seth E. Meek as Salmo jordani, the "spotted trout" of Lake Southerland, and Salmo declivifrons, the "salmon-trout." These seem to be distinct forms or subspecies produced through isolation.
The Rio Grande trout (Salmo clarkii spilurus) is a large and profusely spotted trout, found in the head-waters of the Rio Grande, the mountain streams of the Great Basin of Utah, and as far south as the northern part of Chihuahua. Its scales are still smaller than those of the ordinary cutthroat-trout, and the black spots are chiefly confined to the tail. Closely related to it is the trout of the Colorado Basin, Salmo clarkii pleuriticus, a large and handsome trout with very small scales, much sought by anglers in western Colorado, and abounding in all suitable streams throughout the Colorado Basin.
=Hucho, the Huchen.=—The genus Hucho has been framed for the Huchen or Rothfisch (Hucho hucho) of the Danube, a very large trout, differing from the genus Salmo in having no teeth on the shaft of the vomer, and from the Salvelini at least in form and coloration. The huchen is a long and slender, somewhat pike-like fish, with depressed snout and strong teeth. The color is silvery, sprinkled with small black dots. It reaches a size little inferior to that of the salmon, and it is said to be an excellent food-fish. In northern Japan is a similar species, Hucho blackistoni, locally known as Ito, a large and handsome trout with very slender body, reaching a length of 2½ feet. It is well worthy of introduction into American and European waters.
=Salvelinus, the Charr.=—The genus Salvelinus comprises the finest of the Salmonidæ, from the point of view of the angler or the artist. In England the species are known as charr or char, in contradistinction to the black-spotted species of Salmo, which are called trout. The former name has unfortunately been lost in America, where the name "trout" is given indiscriminately to both groups, and, still worse, to numerous other fishes (Micropterus, Hexagrammos, Cynoscion, Agonostomus) wholly unlike the Salmonidæ in all respects. It is sometimes said that "the American brook-trout is no trout, nothing but a charr," almost as though "charr" were a word of reproach. Nothing higher, however, can be said of a salmonoid than that it is a "charr." The technical character of the genus Salvelinus lies in the form of its vomer. This is deeper than in Salmo; and when the flesh is removed the bone is found to be somewhat boat-shaped above, and with the shaft depressed and out of the line of the head of the vomer. Only the head or chevron is armed with teeth, and the shaft is covered by skin.
In color all the charrs differ from the salmon and trout. The body in all is covered with round spots which are paler than the ground color, and crimson or gray. The lower fins are usually edged with bright colors. The sexual differences are not great. The scales, in general, are smaller than in other Salmonidæ, and they are imbedded in the skin to such a degree as to escape the notice of casual observers and even of most anglers.
"One trout scale in the scales I'd lay (If trout had scales), and 'twill outweigh The wrong side of the balances."—LOWELL.
The charrs inhabit, in general, only the clearest and coldest of mountain streams and lakes, or bays of similar temperature. They are not migratory, or only to a limited extent. In northern regions they descend to the sea, where they grow much more rapidly and assume a nearly uniform silvery-gray color. The different species are found in all suitable waters throughout the northern parts of both continents, except in the Rocky Mountains and Great Basin, where only the black-spotted trout occur. The number of species of charr is very uncertain, as, both in America and Europe, trivial variations and individual peculiarities have been raised to the rank of species. More types, however, seem to be represented in America than in Europe.
The only really well-authenticated species of charr in European waters is the red charr, sälbling, or ombre chevalier (Salvelinus alpinus). This species is found in cold, clear streams in Switzerland, Germany, and throughout Scandinavia and the British Islands. Compared with the American charr or brook-trout, it is a slenderer fish, with smaller mouth, longer fins, and smaller red spots, which are confined to the sides of the body. It is a "gregarious and deep-swimming fish, shy of taking the bait and feeding largely at night-time. It appears to require very pure and mostly deep water for its residence." It is less tenacious of life than the trout. It reaches a weight of from one to five pounds, probably rarely exceeding the latter in size. The various charr described from Siberia are far too little known to be enumerated here.
Of the American charr the one most resembling the European species is the Rangeley Lake trout (Salvelinus oquassa). The exquisite little fish is known in the United States only from the Rangeley chain of lakes in western Maine. This is very close to the Greenland charr, Salvelinus stagnalis, a beautiful species of the far north. The Rangeley trout is much slenderer than the common brook-trout, with much smaller head and smaller mouth. In life it is dark blue above, and the deep-red spots are confined to the sides of the body. The species rarely exceeds the length of a foot in the Rangeley Lakes, but in some other waters it reaches a much larger size. So far as is known it keeps itself in the depths of the lake until its spawning season approaches, in October, when it ascends the stream to spawn.
Still other species of this type are the Sunapee trout, Salvelinus aureolus, a beautiful charr almost identical with the European species, found in numerous ponds and lakes of eastern New Hampshire and neighboring parts of Maine. Mr. Garman regards this trout as the offspring of an importation of the ombre chevalier and not as a native species, and in this view he may be correct. Salvelinus alipes of the far north may be the same species. Another remarkable form is the Lac de Marbre trout of Canada, Salvelinus marstoni of Garman.
In Arctic regions another species, called Salvelinus naresi, is very close to Salvelinus oquassa and may be the same.
Another beautiful little charr, allied to Salvelinus stagnalis, is the Floeberg charr (Salvelinus arcturus). This species has been brought from Victoria Lake and Floeberg Beach, in the extreme northern part of Arctic America, the northernmost point whence any salmonoid has been obtained.
The American charr, or, as it is usually called, the brook-trout (Salvelinus fontinalis), although one of the most beautiful of fishes, is perhaps the least graceful of all the genuine charrs. It is technically distinguished by the somewhat heavy head and large mouth, the maxillary bone reaching more or less beyond the eye. There are no teeth on the hyoid bone, traces at least of such teeth being found in nearly all other species. Its color is somewhat different from that of the others, the red spots being large and the black more or less mottled and barred with darker olive. The dorsal and caudal fins are likewise barred or mottled, while in the other species they are generally uniform in color. The brook-trout is found only in streams east of the Mississippi and Saskatchewan. It occurs in all suitable streams of the Alleghany region and the Great Lake system, from the Chattahoochee River in northern Georgia northward at least to Labrador and Hudson Bay, the northern limits of its range being as yet not well ascertained. It varies greatly in size, according to its surroundings, those found in lakes being larger than those resident in small brooks. Those found farthest south, in the head-waters of the Chattahoochee, Savannah, Catawba, and French Broad, rarely pass the dimensions of fingerlings. The largest specimens are recorded from the sea along the Canadian coast. These frequently reach a weight of ten pounds; and from their marine and migratory habits, they have been regarded as forming a distinct variety (Salvelinus fontinalis immaculatus), but this form is merely a sea-run brook-trout. The largest fresh-water specimens rarely exceed seven pounds in weight. Some unusually large brook-trout have been taken in the Rangeley Lakes, the largest known to me having a reputed weight of eleven pounds. The brook-trout is the favorite game-fish of American waters, preëminent in wariness, in beauty, and in delicacy of flesh. It inhabits all clear and cold waters within its range, the large lakes and the smallest ponds, the tiniest brooks and the largest rivers; and when it can do so without soiling its aristocratic gills on the way, it descends to the sea and grows large and fat on the animals of the ocean. Although a bold biter it is a wary fish, and it often requires much skill to capture it. It can be caught, too, with artificial or natural flies, minnows, crickets, worms, grasshoppers, grubs, the spawn of other fish, or even the eyes or cut pieces of other trout. It spawns in the fall, from September to late in November. It begins to reproduce at the age of two years, then having a length of about six inches. In spring-time the trout delight in rapids and swiftly running water; and in the hot months of midsummer they resort to deep, cool, and shaded pools. Later, at the approach of the spawning season, they gather around the mouths of cool, gravelly brooks, whither they resort to make their beds.[10]
Footnote 10:
Hallock.
The trout are rapidly disappearing from our streams through the agency of the manufacturer and the summer boarder. In the words of an excellent angler, the late Myron W. Reed of Denver: "This is the last generation of trout-fishers. The children will not be able to find any. Already there are well-trodden paths by every stream in Maine, in New York, and in Michigan. I know of but one river in North America by the side of which you will find no paper collar or other evidence of civilization. It is the Nameless River. Not that trout will cease to be. They will be hatched by machinery and raised in ponds, and fattened on chopped liver, and grow flabby and lose their spots. The trout of the restaurant will not cease to be. He is no more like the trout of the wild river than the fat and songless reedbird is like the bobolink. Gross feeding and easy pond-life enervate and deprave him. The trout that the children will know only by legend is the gold-sprinkled, living arrow of the white water; able to zigzag up the cataract; able to loiter in the rapids; whose dainty meat is the glancing butterfly."
The brook-trout adapts itself readily to cultivation in artificial ponds. It has been successfully transported to Europe, and it is already abundant in certain streams in England, in California, and elsewhere.
In Dublin Pond, New Hampshire, is a gray variety without red spots, called Salvelinus agassizi.
The "Dolly Varden" trout, or malma (Salvelinus malma), is very similar to the brook-trout, closely resembling it in size, form, color, and habits. It is found always to the westward of the Rocky Mountains, in the streams of northern California, Oregon, Washington, and British Columbia, Alaska, and Kamchatka, as far as the Kurile Islands. It abounds in the sea in the northward, and specimens of ten to twelve pounds weight are not uncommon in Puget Sound and especially in Alaska. The Dolly Varden trout is, in general, slenderer and less compressed than the Eastern brook-trout. The red spots are found on the back of the fish as well as on the sides, and the back and upper fins are without the blackish marblings and blotches seen in Salvelinus fontinalis. In value as food, in beauty, and in gaminess Salvelinus malma is very similar to its Eastern cousin.
In Alaska the Dolly Varden, locally known as salmon-trout, is very destructive to the eggs of the salmon, and countless numbers are taken in the salmon-nets of Alaska and thrown away as useless by the canners. In every coastwise stream of Alaska the water fairly "boils" with these trout. They are, however, not found in the Yukon. In northern Japan occurs Salvelinus pluvius, the iwana, a species very similar to the Dolly Varden, but not so large or so brightly colored. In the Kurile region and Kamchatka is another large charr, Salvelinus kundscha, with the spots large and cream-color instead of crimson.
=Cristivomer, the Great Lake Trout.=—Allied to the true charrs, but now placed by us in a different genus, Cristivomer, is the Great Lake trout, otherwise known as Mackinaw trout, longe, or togue (Cristivomer namaycush). Technically this fish differs from the true charrs in having on its vomer a raised crest behind the chevron and free from the shaft. This crest is armed with strong teeth. There are also large hooked teeth on the hyoid bone, and the teeth generally are proportionately stronger than in most of the other species. The Great Lake trout is grayish in color, light or dark according to its surroundings; and the body is covered with round paler spots, which are gray instead of red. The dorsal and caudal fins are marked with darker reticulations, somewhat as in the brook-trout. This noble species is found in all the larger lakes from New England and New York to Wisconsin, Montana, the Mackenzie River, and in all the lakes tributary to the Yukon in Alaska. We have taken examples from Lake Bennett, Lake Tagish, Summit Lake (White Pass), and have seen specimens from Lake La Hache in British Columbia. It reaches a much larger size than any Salvelinus, specimens of from fifteen to twenty pounds weight being not uncommon, while it occasionally attains a weight of fifty to eighty pounds. As a food-fish it ranks high, although it may be regarded as somewhat inferior to the brook-trout or the whitefish. Compared with other salmonoids, the Great Lake trout is a sluggish, heavy, and ravenous fish. It has been known to eat raw potato, liver, and corn-cobs,—refuse thrown from passing steamers. According to Herbert, "a coarse, heavy, stiff rod, and a powerful oiled hempen or flaxen line, on a winch, with a heavy sinker; a cod-hook, baited with any kind of flesh, fish, or fowl,—is the most successful, if not the most orthodox or scientific, mode of capturing him. His great size and immense strength alone give him value as a fish of game; but when hooked he pulls strongly and fights hard, though he is a boring, deep fighter, and seldom if ever leaps out of the water, like the true salmon or brook-trout."
In the depths of Lake Superior is a variety of the Great Lake trout known as the Siscowet (Cristivomer namaycush siskawitz), remarkable for its extraordinary fatness of flesh. The cause of this difference lies probably in some peculiarity of food as yet unascertained.
=The Ayu, or Sweetfish.=—The ayu, or sweetfish, of Japan, Plecoglossus altivelis, resembles a small trout in form, habits, and scaling. Its teeth are, however, totally different, being arranged on serrated plates on the sides of the jaws, and the tongue marked with similar folds. The ayu abounds in all clear streams of Japan and Formosa. It runs up from the sea like a salmon. It reaches the length of about a foot. The flesh is very fine and delicate, scarcely surpassed by that of any other fish whatsoever. It should be introduced into clear short streams throughout the temperate zones.
In the river at Gifu in Japan and in some other streams the ayu is fished for on a large scale by means of tamed cormorants. This is usually done from boats in the night by the light of torches.
=Cormorant-fishing.=—The following account of cormorant-fishing is taken, by the kind permission of Mr. Caspar W. Whitney, from an article contributed by the writer to Outing, April, 1902:
Tamagawa means Jewel River, and no water could be clearer. It rises somewhere up in the delectable mountains to the eastward of Musashi, among the mysterious pines and green-brown fir-trees, and it flows across the plains bordered by rice-fields and mulberry orchards to the misty bay of Tokyo. It is, therefore, a river of Japan, and along its shores are quaint old temples, each guarding its section of primitive forest, picturesque bridges, huddling villages, and torii, or gates through which the gods may pass.
The stream itself is none too large—a boy may wade it—but it runs on a wide bed, which it will need in flood-time, when the snow melts in the mountains. And this broad flood-bed is filled with gravel, with straggling willows, showy day-lilies, orange amaryllis, and the little sky-blue spider-flower, which the Japanese call chocho, or butterfly-weed.
In the Tamagawa are many fishes: shining minnows in the white ripples, dark catfishes in the pools and eddies, and little sculpins and gobies lurking under the stones. Trout dart through its upper waters, and at times salmon run up from the sea.
But the one fish of all its fishes is the ayu. This is a sort of dwarf salmon, running in the spring and spawning in the rivers just as a salmon does. But it is smaller than any salmon, not larger than a smelt, and its flesh is white and tender, and so very delicate in its taste and odor that one who tastes it crisply fried or broiled feels that he has never tasted real fish before. In all its anatomy the ayu is a salmon, a dwarf of its kind, one which our ancestors in England would have called a "samlet." Its scientific name is Plecoglossus altivelis. Plecoglossus means plaited tongue, and altivelis, having a high sail; for the skin of the tongue is plaited or folded in a curious way, and the dorsal fin is higher than that of the salmon, and one poetically inclined might, if he likes, call it a sail. The teeth of the ayu are very peculiar, for they constitute a series of saw-edged folds or plaits along the sides of the jaws, quite different from those of any other fish whatsoever.
In size the ayu is not more than a foot to fifteen inches long. It is like a trout in build, and its scales are just as small. It is light yellowish or olive in color, growing silvery below. Behind its gills is a bar of bright shining yellow, and its adipose fin is edged with scarlet. The fins are yellow, and the dorsal fin shaded with black, while the anal fin is dashed with pale red.
So much for the river and the ayu. It is time for us to go afishing. It is easy enough to find the place, for it is not more than ten miles out of Tokyo, on a fine old farm just by the ancient Temple of Tachikawa, with its famous inscribed stone, given by the emperor of China.
At the farmhouse, commodious and hospitable, likewise clean and charming after the fashion of Japan, we send for the boy who brings our fishing-tackle.
They come waddling into the yard, the three birds with which we are to do our fishing. Black cormorants they are, each with a white spot behind its eye, and a hoarse voice, come of standing in the water, with which it says y-eugh whenever a stranger makes a friendly overture. The cormorants answer to the name of Ou, which in Japanese is something like the only word the cormorants can say. The boy puts them in a box together and we set off across the drifted gravel to the Tamagawa. Arrived at the stream, the boy takes the three cormorants out of the box and adjusts their fishing-harness. This consists of a tight ring about the bottom of the neck, of a loop under each wing, and a directing line.
Two other boys take a low net. They drag it down the stream, driving the little fishes—ayu, zakko, haë, and all the rest—before it. The boy with the cormorants goes in advance. The three birds are eager as pointer dogs, and apparently full of perfect enjoyment. To the right and left they plunge with lightning strokes, each dip bringing up a shining fish. When the bird's neck is full of fishes down to the level of the shoulders, the boy draws him in, grabs him by the leg, and shakes him unceremoniously over a basket until all the fishes have flopped out.
The cormorants watch the sorting of the fish with eager eyes and much repeating of y-eugh, the only word they know. The ayu are not for them, and some of the kajikas and hazés were prizes of science. But zakko (the dace) and haë (the minnow) were made for the cormorant. The boy picks out the chubs and minnows and throws them to one bird and then another. Each catches his share on the fly, swallows it at one gulp, for the ring is off his neck by this time, and then says y-eugh, which means that he likes the fun, and when we are ready will be glad to try again. And no doubt they have tried it many times since, for there are plenty of fishes in the Jewel River, zakko and haë as well as ayu.
=Fossil Salmonidæ.=—Fossil salmonidæ are rare and known chiefly from detached scales, the bones in this family being very brittle and easily destroyed. Nothing is added to our knowledge of the origin of these fishes from such fossils.
A large fossil trout or salmon, called Rhabdofario lacustris, has been brought from the Pliocene at Catherine's Creek, Idaho. It is known from the skull only. Thaumaturus luxatus, from the Miocene of Bohemia, shows the print of the adipose fin. As already stated (p. 62), fragments of the hooked jaws of salmon, from pleistocene deposits in Idaho, are in the museum of the University of California.
VI. THE GRAYLING AND THE SMELT
=THE Grayling, or Thymallidæ.=—The small family of Thymallidæ, or grayling, is composed of finely organized fishes allied to the trout, but differing in having the frontal bones meeting on the middle line of the skull, thus excluding the frontals from contact with the supraoccipital. The anterior half of the very high dorsal is made up of unbranched simple rays. There is but one genus, Thymallus, comprising very noble game-fishes characteristic of subarctic streams.
The grayling, Thymallus, of Europe, is termed by Saint Ambrose "the flower of fishes." The teeth on the tongue, found in all the trout and salmon, are obsolete in the grayling. The chief distinctive peculiarity of the genus Thymallus is the great development of the dorsal fin, which has more rays (20 to 24) than are found in any of the Salmonidæ, and the fin is also higher. All the species are gaily colored, the dorsal fin especially being marked with purplish or greenish bands and bright rose-colored spots; while the body is mostly purplish gray, often with spots of black. Most of the species rarely exceed a foot in length, but northward they grow larger. Grayling weighing five pounds have been taken in England; and according to Dr. Day they are said in Lapland to reach a weight of eight or nine pounds. The grayling in all countries frequent clear, cold brooks, and rarely, if ever, enter the sea, or even the larger lakes. They congregate in small shoals in the streams, and prefer those which have a succession of pools and shallows, with a sandy or gravelly rather than rocky bottom. The grayling spawns on the shallows in April or May (in England). It is non-migratory in its habits, depositing its ova in the neighborhood of its usual haunts. The ova are far more delicate and easily killed than those of the trout or charr. The grayling and the trout often inhabit the same waters, but not altogether in harmony. It is said that the grayling devours the eggs of the trout. It is certain that the trout feed on the young grayling. As a food-fish, the grayling of course ranks high; and it is beloved by the sportsman. They are considered gamy fishes, although less strong than the brook-trout, and perhaps less wary. The five or six known species of grayling are very closely related, and are doubtless comparatively recent offshoots from a common stock, which has now spread itself widely through the northern regions.
The common grayling of Europe (Thymallus thymallus) is found throughout northern Europe, and as far south as the mountains of Hungary and northern Italy. The name Thymallus was given by the ancients, because the fish, when fresh, was said to have the odor of water-thyme. Grayling belonging to this or other species are found in the waters of Russia and Siberia.
The American grayling (Thymallus signifer) is widely distributed in British America and Alaska. In the Yukon it is very abundant, rising readily to the fly. In several streams in northern Michigan, Au Sable River, and Jordan River in the southern peninsula, and Otter Creek near Keweenaw in the northern peninsula, occurs a dwarfish variety or species with shorter and lower dorsal fins, known to anglers as the Michigan grayling (Thymallus tricolor). This form has a longer head, rather smaller scales, and the dorsal fin rather lower than in the northern form (signifer); but the constancy of these characters in specimens from intermediate localities is yet to be proved. Another very similar form, called Thymallus montanus, occurs in the Gallatin, Madison, and other rivers of Western Montana tributary to the Missouri. It is locally still abundant and one of the finest of game-fishes. It is probable that the grayling once had a wider range to the southward than now, and that so far as the waters of the United States are concerned it is tending toward extinction. This tendency is, of course, being accelerated in Michigan by lumbermen and anglers. The colonies of grayling in Michigan and Montana are probably remains of a post-glacial fauna.
=The Argentinidæ.=—The family of Argentinidæ, or smelt, is very closely related to the Salmonidæ, representing a dwarf series of similar type. The chief essential difference lies in the form of the stomach, which is a blind sac, the two openings near together, and about the second or pyloric opening there are few if any pyloric cæca. In all the Salmonidæ the stomach has the form of a siphon, and about the pylorus there are very many pyloric cæca. The smelt have the adipose fin and the general structure of the salmon. All the species are small in size, and most of them are strictly marine, though some of them ascend the rivers to spawn, just as salmon do, but not going very far. A few kinds become landlocked in ponds. Most of the species are confined to the north temperate zone, and a few sink into the deep seas. All that are sufficiently abundant furnish excellent food, the flesh being extremely delicate and often charged with a fragrant oil easy of digestion.
The best-known genus, Osmerus, includes the smelt, or spirling (éperlan), of Europe, and its relatives, all excellent food-fishes, although quickly spoiling in warm weather. Osmerus eperlanus is the European species; Osmerus mordax of our eastern coast is very much like it, as is also the rainbow-smelt, Osmerus dentex of Japan and Alaska. A larger smelt, Osmerus albatrossis, occurs on the coast of Alaska, and a small and feeble one, Osmerus thaleichthys, mixed with other small or delicate fishes, is the whitebait of the San Francisco restaurants. The whitebait of the London epicure is made up of the young of herrings and sprats of different species. The still more delicate whitebait of the Hong Kong hotels is the icefish, Salanx chinensis. Retropinna retropinna, so called from the backward insertion of its dorsal, is the excellent smelt of the rivers of New Zealand. All the other species belong to northern waters. Mesopus, the surf-smelt, has a smaller mouth than Osmerus and inhabits the North Pacific. The California species, Mesopus pretiosus, of Neah Bay has, according to James G. Swan, "the belly covered with a coating of yellow fat which imparts an oily appearance to the water where the fish has been cleansed or washed and makes them the very perfection of pan-fish." This species spawns in late summer along the surf-line. According to Mr. Swan the water seems to be filled with them. "They come in with the flood-tide, and when a wave breaks upon the beach they crowd up into the very foam, and as the surf recedes many will be seen flapping on the sand and shingle, but invariably returning with the undertow to deeper water." The Quilliute Indians of Washington believe that "the first surf-smelts that appear must not be sold or given away to be taken to another place, nor must they be cut transversely, but split open with a mussel-shell."
The surf-smelt is marine, as is also a similar species, Mesopus japonicus, in Japan. Mesopus olidus, the pond-smelt of Alaska, Kamchatka, and Northern Japan, spawns in fresh-water ponds.
Still more excellent as a food-fish than even these exquisite species is the famous eulachon, or candle-fish (Thaleichthys pacificus). The Chinook name, usually written eulachon, is perhaps more accurately represented as ulchen. This little fish has the form of a smelt and reaches the length of nearly a foot. In the spring it ascends in enormous numbers all the rivers north of the Columbia, as far as Skaguay, for a short distance for the purpose of spawning. These runs take place usually in advance of the salmon-runs. Various predatory fishes and sea-birds persecute the eulachon during its runs, and even the stomachs of the sturgeons are often found full of the little fishes, which they have taken in by their sucker-like mouths. At the time of the runs the eulachon are extremely fat, so much so that it is said that when dried and a wick drawn through the body they may be used as candles. On Nass River, in British Columbia, a stream in which their run is greatest, there is a factory for the manufacture of eulachon-oil from them. This delicate oil is proposed as a substitute for cod-liver oil in medicine. Whatever may be its merits in this regard, it has the disadvantage in respect to salability of being semi-solid or lard-like at ordinary temperatures, requiring melting to make it flow as oil. The eulachon is a favorite pan-fish in British Columbia. The writer has had considerable experience with it, broiled and fried, in its native region, and has no hesitation in declaring it to be the best-flavored food-fish in American waters. It is fat, tender, juicy, and richly flavored, with comparatively few troublesome bones. It does not, however, bear transportation well. The Indians in Alaska bury the eulachon in the ground in great masses. After the fish are well decayed they are taken out and the oil pressed from them. The odor of the fish and the oil is then very offensive, less so, however, than that of some forms of cheese eaten by civilized people.
The capelin (Mallotus villosus) closely resembles the eulachon, differing mainly in its broader pectorals and in the peculiar scales of the males. In the male fish a band of scales above the lateral line and along each side of the belly become elongate, closely imbricated, with the free points projecting, giving the body a villous appearance. It is very abundant on the coasts of Arctic America, both in the Atlantic and the Pacific, and is an important source of food for the natives of those regions.
This species spawns in the surf, and the writer has seen them in August cast on the shores of the Alaskan islands (as at Metlakahtla in 1897), living and dead, in numbers which seem incredible. The males are then distorted, and it seems likely that all of them perish after spawning. The young are abundant in all the northern fiords. Even more inordinate numbers are reported from the shores of Greenland.
The capelin seems to be inferior to the eulachon as a food-fish, but to the natives of arctic regions in both hemispheres it is a very important article of food. Fossil capelin are found in abundance in recent shales in Greenland enveloped in nodules of clay. In the open waters about the Aleutian Islands a small smelt, Therobromus callorhini, occurs in very great abundance and forms the chief part of the summer food of the fur-seal. Strangely enough, no complete specimen of this fish has yet been seen by man, although thousands of fragments have been taken from seals' stomachs. From these fragments Mr. Frederick A. Lucas has reconstructed the fish, which must be an ally of the surf-smelt, probably spawning in the open ocean of the north.
The silvery species called Argentina live in deeper water and have no commercial importance. Argentina silus, with prickly scales, occurs in the North Sea. Several fossils have been doubtfully referred to Osmerus.
=The Microstomidæ.=—The small family of Microstomidæ consists of a few degraded smelt, slender in form, with feeble mouth and but three or four branchiostegals, rarely taken in the deep seas. Nansenia grœnlandica was found by Reinhardt off the coast of Greenland, and six or eight other species of Microstoma and Bathylagus have been brought in by the deep-sea explorations.
=The Salangidæ, or Icefishes.=—Still more feeble and insignificant are the species of Salangidæ, icefishes, or Chinese whitebait, which may be described as Salmonidæ reduced to the lowest terms. The body is long and slender, perfectly translucent, almost naked, and with the skeleton scarcely ossified. The fins are like those of the salmon, the head is depressed, the jaws long and broad, somewhat like the bill of a duck, and within there are a few disproportionately strong canine teeth, those of the lower jaw somewhat piercing the upper. The alimentary canal is straight for its whole length, without pyloric cæca. These little fishes, two to five inches long, live in the sea in enormous numbers and ascend the rivers of eastern Asia for the purpose of spawning. It is thought by some that they are annual fishes, all dying in the fall after reproduction, the species living through the winter only within its eggs. But this is only suspected, not proved, and the species will repay the careful study which some of the excellent naturalists of Japan are sure before long to give to it. The species of Salanx are known as whitebait, in Japan as Shiro-uwo, which means exactly the same thing. They are also sometimes called icefish (Hingio), which, being used for no other fish, may be adopted as a group name for Salanx.
The species are Salanx chinensis from Canton, Salanx hyalo cranius from Korea and northern China, Salanx microdon from northern Japan, and Salanx ariakensis from the southern island of Kiusiu. The Japanese fishes are species still smaller and feebler than their relatives from the mainland.
=The Haplochitonidæ.=—The Haplochitonidæ are trout-like fishes of the south temperate zone, differing from the Salmonidæ mainly in the extension of the premaxillary until, as in the perch-like fishes, it forms the outer border of the upper jaw. The adipose fin is present as in all the salmon and smelt. Haplochiton of Tierra del Fuego and the Falkland Islands is naked, while in Prototroctes of Australia and New Zealand the body, as in all salmon, trout, and smelt, is covered with scales. Prototroctes maræna is the yarra herring of Australia. The closely related family of Galaxiidæ, also Australian, but lacking the adipose fin, is mentioned in a later chapter.
=Stomiatidæ.=—The Stomiatidæ, with elongate bodies, have the mouth enormous, with fang-like teeth, usually barbed. Of the several species Stomias ferox is best known. According to Dr. Boulenger, these fishes are true Isospondyli.
Astronesthidæ is another small group of small fishes naked and black, with long canines, found in the deep sea.
The Malacosteidæ is a related group with extremely distensible mouth, the species capable of swallowing fishes much larger than themselves.
The viper-fishes (Chauliodontidæ) are very feeble and very voracious little fishes occasionally brought up from the depths. Chauliodus sloanei is notable for the length of the fangs.
Much smaller and feebler are the species of the closely related family of Gonostomidæ. Gonostoma and Cyclothone dwell in oceanic abysses. One species, Cyclothone elongata, occurs at the depth of from half a mile to nearly four miles almost everywhere throughout the oceans. It is probably the most widely distributed, as well as one of the feeblest and most fragile, of all bassalian or deep-sea fishes.
=Suborder Iniomi, the Lantern-fishes.=—The suborder Iniomi (ἰνίον, nape; ὤμος, shoulder) comprises soft-rayed fishes, in which the shoulder-girdle has more or less lost its completeness of structure as part of the degradation consequent on life in the abysses of the sea. These features distinguish these forms from the true Isospondyli, but only in a very few of the species have these characters been verified by actual examination of the skeleton. The mesocoracoid arch is wanting or atrophied in all of the species examined, and the orbitosphenoid is lacking, so far as known. The group thus agrees in most technical characters with the Haplomi, in which group they are placed by Dr. Boulenger. On the other hand the relationships to the Isospondyli are very close, and the Iniomi have many traits suggesting degenerate Isospondyli. The post-temporal has lost its usual hold on the skull and may touch the occiput on the sides of the cranium. Nearly all the species are soft in body, black or silvery over black in color, and all that live in the deep sea are provided with luminous spots or glands giving light in the abysmal depths. These spots are wanting in the few shore species, as also in those which approach most nearly to the Salmonidæ, these being presumably the most primitive of the group. In these also the post-temporal touches the back of the cranium near the side. In the majority of the Iniomi the adipose fin of the Salmonidæ is retained. From the phosphorescent spots is derived the general name of lantern-fishes applied of late years to many of the species. Most of these are of recent discovery, results of the remarkable work in deep-sea dredging begun by the Albatross and the Challenger. All of the species are carnivorous, and some, in spite of their feeble muscles, are exceedingly voracious, the mouth being armed with veritable daggers and spears.
=Aulopidæ.=—Most primitive of the Iniomi is the family of Aulopidæ, having an adipose fin, a normal maxillary, and no luminous spots. The rough firm scales suggest those of the berycoid fishes. The few species of Aulopus and Chlorophthalmus are found in moderate depths. Aulopus purpurissatus is the "Sergeant Baker" of the Australian fishermen.
=The Lizard-fishes.=—The Synodontidæ, or lizard-fishes, have lizard-like heads with very large mouth. The head is scaly, a character rare among the soft-rayed fishes. The slender maxillary is grown fast to the premaxillary, and the color is not black. Most of the species are shore-fishes and some are brightly colored. Synodus fætens is the common lizard-fish, or galliwasp, of our Atlantic coast. Synodus varius of the Pacific is brightly colored, olive-green and orange-red types of coloration existing at different depths. Most of the species lie close to the bottom and are mottled gray like coral sand. A few occur in oceanic depths. The "Bombay duck" of the fishermen of India is a species of Harpodon, H. nehereus, with large mouth and arrow-shaped teeth. The dried fish is used as a relish.
The Benthosauridæ are deep-sea fishes of similar type, but with distinct maxillaries. The Bathypteroidæ, of the deep seas, resemble Aulopus, but have the upper and lower pectoral rays filiform, developed as organs of touch in the depths in which the small eyes become practically useless.
=Ipnopidæ.=—In the Ipnopidæ the head is depressed above and the two eyes are flattened and widened so as to occupy most of its upper surface. These structures were at first supposed to be luminous organs, but Professor Moseley has shown them to be eyes. "They show a flattened cornea extending along the median line of the snout, with a large retina composed of peculiar rods which form a complicated apparatus destined undoubtedly to produce an image and to receive especial luminous rays." The single species, Ipnops murrayi, is black in color and found at the depth of 2½ miles in various seas.
The existence of well-developed eyes among fishes destined to live in the dark abysses of the ocean seems at first contradictory, but we must remember that these singular forms are descendants of immigrants from the shore and from the surface. "In some cases the eyes have not been specially modified, but in others there have been modifications of a luminous mucous membrane leading on the one hand to phosphorescent organs more or less specialized, or on the other to such remarkable structures as the eyes of Ipnops, intermediate between true eyes and phosphorescent plates. In fishes which cannot see, and which retain for their guidance only the general sensibility of the integuments and the lateral line, these parts soon acquire a very great delicacy. The same is the case with tactile organs (as in Bathypterois and Benthosaurus), and experiments show that barbels may become organs of touch adapted to aquatic life, sensitive to the faintest movements or the slightest displacement, with power to give the blinded fishes full cognizance of the medium in which they live."
=Rondeletiidæ.=—The Rondeletiidæ are naked black fishes with small eyes, without adipose fin and without luminous spots, taken at great depths in the Atlantic. The relationship of these fishes is wholly uncertain.
The Cetomimidæ are near allies of the Rondeletiidæ, having the mouth excessively large, with the peculiar form seen in the right whales, which these little fishes curiously resemble.
=Myctophidæ.=—The large family of Myctophidæ, or lantern-fishes, is made up of small fishes allied to the Aulopidæ, but with the body covered with luminous dots, highly specialized and symmetrically arranged. Most of them belong to the deep sea, but others come to the surface in the night or during storms when the sunlight is absent. Through this habit they are often thrown by the waves on the decks of small vessels. Largely from Danish merchant-vessels, Dr. Lütken has obtained the unrivaled collection of these sea-waifs preserved in the Museum of the University of Copenhagen. The species are all small in size and feeble in structure, the prey of the larger fishes of the depths, from which their lantern-like spots and large eyes help them to escape. The numerous species are now ranged in about fifteen genera, although earlier writers placed them all in a single genus Myctophum (Scopelus).
In the genus Diaphus (Æthoprora) there is a large luminous gland on the end of the short snout, like the headlight of an engine. In Dasyscopelus the scales are spinescent, but in most of the genera, as in Myctophum, the scales are cycloid and caducous, falling at the touch. In Diaphus the luminous spots are crossed by a septum giving them the form of the Greek letter θ (theta). One of the commonest species is Myctophum humboldti.
=Chirothricidæ.=—The remarkable extinct family of Chirothricidæ may be related to the Synodontidæ, or Myctophidæ. In this group the teeth are feeble, the paired fins much enlarged, and the ventrals are well forward. The dorsal fin, inserted well forward, has stout basal bones. Chirothrix libanicus of the Cretaceous of Mt. Lebanon is remarkable for its excessively large ventral fins. Telepholis is a related genus. Exocœtoides with rounded caudal fin is probably the type of a distinct family, Exocœtoididæ, the caudal fin being strongly forked in Chirothrix. The small extinct group of Rhinellidæ is usually placed near the Myctophidæ. They are distinguished by the very long gar-like jaws; whether they possessed adipose fins or luminous spots cannot be determined. Rhinellus furcatus and other species occur in the Cretaceous of Europe and Asia. Fossil forms more or less distinctly related to the Myctophidæ are numerous. Osmeroides monasterii (wrongly called Sardinioides), from the German Cretaceous, seems allied to Myctophum, although, of course, luminous spots leave no trace among fossils. Acrognathus boops is remarkable for the large size of the eyes.
=Maurolicidæ.=—The Maurolicidæ are similar in form and habit, but scaleless, and with luminous spots more highly specialized. Maurolicus pennanti, the "Sleppy Argentine," is occasionally taken on either side of the Atlantic. Other genera are Zalarges, Vinciguerria, and Valenciennellus.
=The Lancet-fishes.=—The Plagyodontidæ (Alepisauridæ) contains the lancet-fishes, large, swift, scaleless fishes of the ocean depths with very high dorsal fin, and the mouth filled with knife-like teeth. These large fish are occasionally cast up by storms or are driven to the shores by the torments of a parasite, Tetrarhynchus, found imbedded in the flesh.
It is probable that they are sometimes killed by being forced above their level by fishes which they have swallowed. In such cases they are destroyed through the reduction of pressure.
Every part of the body is so fragile that perfect specimens are rare. The dorsal fin is readily torn, the bones are very feebly ossified, and the ligaments connecting the vertebræ are very loose and extensible, so that the body can be considerably stretched. "This loose connection of the parts of the body is found in numerous deep-sea fishes, and is merely the consequence of their withdrawal from the pressure of the water to which they are exposed in the depths inhabited by them. When within the limits of their natural haunts, the osseous, muscular, and fibrous parts of the body will have that solidity which is required for the rapid and powerful movements of a predatory fish. That the fishes of this genus (Plagyodus) belong to the most ferocious of the class is proved by their dentition and the contents of their stomach." (Günther.) Dr. Günther elsewhere observes: "From the stomach of one example have been taken several octopods, crustaceans, ascidians, a young Brama, twelve young boarfishes (Capros), a horse-mackerel, and one young of its own species."
The lancet-fish, Plagyodus ferox, is occasionally taken on either side of the Atlantic and in Japan. The handsaw-fish, called Plagyodus æsculapius, has been taken at Unalaska, off San Luis Obispo, and in Humboldt Bay. It does not seem to differ at all from Plagyodus ferox. The original type from Unalaska had in its stomach twenty-one lumpfishes (Eumicrotremus spinosus). This is the species described from Steller's manuscripts by Pallas under the name of Plagyodus. Another species, Plagyodus borcalis, is occasionally taken in the North Pacific.
The Evermannellidæ is a small family of small deep-sea fishes with large teeth, distensible muscles, and an extraordinary power of swallowing other fishes, scarcely surpassed by Chiasmodon or Saccopharynx. Evermannella (Odontostomus, the latter name preoccupied) and Omosudis are the principal genera.
The Paralepidæ are reduced allies of Plagyodus, slender, silvery, with small fins and fang-like jaws. As in Plagyodus, the adipose fin is developed and there are small luminous dots. The species are few and mostly northern; one of them, Sudis ringens, is known only from a single specimen taken by the present writer from the stomach of a hake (Merluccius productus), the hake in turn swallowed whole by an albacore in the Santa Barbara Channel. The Sudis had been devoured by the hake, the hake by the albacore, and the albacore taken on the hook before the feeble Sudis had been digested.
Perhaps allied to the Plagyodontidæ is also the large family of Enchodontidæ, widely represented in the Cretaceous rocks of Syria, Europe, and Kansas. The body in this group is elongate, the teeth very strong, and the dorsal fin short. Enchodus lewesiensis is found in Mount Lebanon, Halec sternbergi in the German Cretaceous, and many species of Enchodus in Kansas; Cimolichthys dirus in North Dakota.
Remotely allied to these groups is the extinct family of Dercetidæ from the Cretaceous of Germany and Syria. These are elongate fishes, the scales small or wanting, but with two or more series of bony scutes along the flanks. In Dercetis scutatus the scutes are large and the dorsal fin is very long. Other genera are Leptotrachelus and Pelargorhynchus. Dr. Boulenger places the Dercetidæ in the order Heteromi. This is an expression of the fact that their relations are still unknown. Probably related to the Dercetidæ is the American family of Stratodontidæ with its two genera, Stradodus and Empo from the Cretaceous (Niobrara) deposits of Kansas. Empo nepaholica is one of the best-known species.
=The Sternoptychidæ.=—The Sternoptychidæ differ materially from all these forms in the short, compressed, deep body and distorted form. The teeth are small, the body bright silvery, with luminous spots. The species live in the deep seas, rising in dark or stormy weather. Sternoptyx diaphana is found in almost all seas, and species of Argyropelecus are almost as widely distributed. After the earthquakes in 1896, which engulfed the fishing villages of Rikuzen, in northern Japan, numerous specimens of this species were found dead, floating on the water, by the steamer Albatross.
The Idiacanthidæ are small deep-sea fishes, eel-shaped and without pectorals, related to the Iniomi.
=Order Lyopomi.=—Other deep-sea fishes constitute the order or suborder Lyopomi (λυός, loose; πῶμα, opercle). These are elongate fishes having no mesocoracoid, and the preopercle rudimentary and connected only with the lower jaw, the large subopercle usurping its place. The group, which is perhaps to be regarded as a degenerate type of Isospondyli, contains the single family of Halosauridæ, with several species, black in color, soft in substance, with small teeth and long tapering tail, found in all seas. The principal genera are Halosaurus and Aldrovandia (Halosauropsis). Aldrovandia macrochira is the commonest species on our Atlantic coast.
Several fossil Halosauridæ are described from the Cretaceous of Europe and Syria, referred to the genera Echidnocephalus and Enchelurus. Boulenger refers the Lyopomi to the suborder Heteromi.
VII. THE APODES, OR EEL-LIKE FISHES
=THE Eels.=—We may here break the sequence from the Isospondyli to the other soft-rayed fishes, to interpolate a large group of uncertain origin, the series or subclass of eels.
The mass of apodal or eel-like fishes has been usually regarded as constituting a single order, the Apodes (ἄ, without; ποῦς, foot). The group as a whole is characterized by the almost universal separation of the shoulder-girdle from the skull, by the absence of the mesocoracoid arch on the shoulder-girdle, by the presence of more than five pectoral actinosts, as in the Ganoid fishes, by the presence of great numbers of undifferentiated vertebræ, giving the body a snake-like form, by the absence in all living forms of the ventral fins, and, in all living forms, by the absence of a separate caudal fin. These structures indicate a low organization. Some of them are certainly results of degeneration, and others are perhaps indications of primitive simplicity. Within the limits of the group are seen other features of degeneration, notably shown in the progressive loss of the bones of the upper jaw and the membrane-bones of the head and the degradation of the various fins. The symplectic bone is wanting, the notochord is more or less persistent, the vertebral centra always complete constricted cylinders, none coalesced. But, notwithstanding great differences in these regards, the forms have been usually left in a single order, the more degraded forms being regarded as descended from the types which approach nearest to the ordinary fishes. From this view Professor Cope dissents. He recognizes several orders of eels, claiming that we should not unite all these various fishes into a single order on account of the eel-like form. If we do so, we should place in another order those with the fish-like form. It is probable, though not absolutely certain, that the Apodes are related to each other. The loss among them, first, of the connection of the post-temporal with the skull; second, of the separate caudal fin and its hypural support; third, of the distinct maxillary and premaxillary; and fourth, of the pectoral fins, must be regarded as successive phases of a general line of degradation. The large number of actinosts, the persistence of the notochord, the absence of spines, and the large numbers of vertebræ seem to be traits of primitive simplicity. Special lines of degeneration are further shown by deep-sea forms. What the origin of the Apodes may have been is not known with any certainty. They are soft-rayed fishes, with the air-bladder connected by a tube with the œsophagus, and with the anterior vertebræ not modified. In so far they agree with the Isospondyli. In some other respects they resemble the lower Ostariophysi, especially the electric eel and the eel-like catfishes. But these resemblances, mainly superficial, may be wholly deceptive; we have no links which certainly connect the most fish-like Apodes with any of the other orders. Probably Woodward's suggestion that they may form a series parallel with the Isospondyli and independently descended from Tertiary Ganoids deserves serious consideration. Perhaps the most satisfactory arrangement of these fishes will be to regard them as constituting four distinct orders for which we may use the names Symbranchia (including Ichthyocephali and Holostomi), Apodes (including Enchelycephali and Colocephali), Carencheli, and Lyomeri.
=Order Symbranchia.=—The Symbranchia are distinguished by the development of the ordinary fish mouth, the maxillary and premaxillary being well developed. The gill-openings are very small, and usually confluent below. These fresh-water forms of the tropics, however eel-like in form, may have no real affinity with the true eels. In any event, they should not be placed in the same order with the latter.
The eels of the suborder Ichthyocephali (ιχθύς, fish; κεφαλή, head) have the head distinctly fish-like. The maxillary, premaxillary, and palatines are well developed, and the shoulder-girdle is joined by a post-temporal to the skull. The body is distinctly eel-like, the tail being very short and the fins inconspicuous. The number of vertebræ is unusually large. The order contains the single family Monopteridæ, the rice-field eels, one species, Monopterus albus, being excessively common in pools and ditches from China and southern Japan to India.
The eels of the suborder Holostomi (ὀλός, complete; στόμα, mouth) differ from these mainly in the separation of the shoulder-girdle from the skull, a step in the direction of the true eels. The Symbranchidæ are very close to the Monopteridæ in external appearance, small, dusky, eel-like inhabitants of sluggish ponds and rivers of tropical America and the East Indies. The gill-openings are confluent under the throat. Symbranchus marmoratus ranges northward as far as Vera Cruz, having much the habit of the rice-field eel of Japan and China. The Amphipnoidæ, with peculiar respiratory structures, abound in India. Amphipnous cuchia, according to Günther, has but three gill-arches, with rudimentary lamina and very narrow slits. To supplement this insufficient branchial apparatus, a lung-like sac is developed on each side of the body behind the head, opening between the hyoid and the first branchial arch. The interior of the sac is abundantly provided with blood-vessels, the arterial coming from the branchial arch, whilst those issuing from it unite to form the aorta. Amphipnous has rudimentary scales. The other Holostomi and Ichthyocephali are naked and all lack the pectoral fin.
The Chilobranchidæ are small sea-fishes from Australia, with the tail longer than the rest of the body, instead of much shorter as in the others.
No forms allied to Symbranchus or Monopterus are recorded as fossils.
=Order Apodes, or True Eels.=—In this group the shoulder-girdle is free from the skull, and the bones of the jaws are reduced in number, through coalescence of the parts.
Three well-marked suborders may be recognized, groups perhaps worthy of still higher rank: Archencheli, Enchelycephali, and Colocephali.
=Suborder Archencheli.=—The Archencheli, now entirely extinct, are apparently the parents of the eels, having, however, certain traits characteristic of the Isospondyli. They retain the separate caudal fin, with the ordinary hypural plate, and Professor Hay has recently found, in an example from the Cretaceous of Mount Lebanon, remains of distinct ventral fins. These traits seem to indicate an almost perfect transition from the Isospondyli to the Archencheli.
One family may be recognized at present, Urenchelyidæ.
The earliest known eel, Urenchelys avus, occurs in the upper Cretaceous at Mount Lebanon. It represents the family Urenchelyidæ, apparently allied to the Anguillidæ, but having a separate caudal fin. Its teeth are small, conical, blunt, in many series. There are more than 100 vertebræ, the last expanded in a hypural. Pectorals present. Scales rudimentary; dorsal arising at the occiput. Branchiostegals slender, not curved around the opercle. Urenchelys anglicus is another species, found in the chalk of England.
=Suborder Enchelycephali.=—The suborder Enchelycephali (ἔγχελυς, eel; κεφαλή, head) contains the typical eels, in which the shoulder-girdle is free from the skull, the palatopterygoid arch relatively complete, the premaxillaries wanting or rudimentary, the ethmoid and vomer coalesced, forming the front of the upper jaw, the maxillaries lateral, and the cranium with a single condyle. In most of the species pectoral fins are present, and the cranium lacks the combined degradation and specialization shown by the morays (Colocephali).
=Family Anguillidæ.=—The most primitive existing family is that of the typical eels, Anguillidæ, which have rudimentary scales oblong in form, and set separately in groups at right angles with one another. These fishes are found in the fresh and brackish waters of all parts of the world, excepting the Pacific coast of North America and the islands of the Pacific. In the upper Great Lakes and the upper Mississippi they are also absent unless introduced. The species usually spawn in the sea and ascend the rivers to feed. But some individuals certainly spawn in fresh water, and none go far into the sea, or where the water is entirely salt. The young eels sometimes ascend the brooks near the sea in incredible numbers, constituting what is known in England as "eel-fairs." They will pass through wet grass to surmount ordinary obstacles. Niagara Falls they cannot pass, and according to Professor Baird "in the spring and summer the visitor who enters under the sheet of water at the foot of the falls will be astonished at the enormous numbers of young eels crawling over the slippery rocks and squirming in the seething whirlpools. An estimate of hundreds of wagon-loads, as seen in the course of the perilous journey referred to, would hardly be considered excessive by those who have visited the spot at a suitable season of the year." "At other times large eels may be seen on their way down-stream, although naturally they are not as conspicuous then as are the hosts of the young on their way upstream. Nevertheless it is now a well-assured fact that the eels are catadromous, that is, that the old descend the watercourses to the salt water to spawn, and the young, at least of the female sex, ascend them to enjoy life in the fresh water."
=Reproduction of the Eel.=—Dr. Gill ("Riverside Natural History," p. 103) gives the following account of the reproduction of Anguilla:
"The generation of the eel was long involved in great mystery, and the knowledge thereof is one of the recent acquisitions of scientific investigation. So late, indeed, as 1880 it was declared that 'their mode of propagation is still unknown.' In want of positive knowledge the rein has been given to loose hypothesis and conjecture. It has been variously asserted that eels were generated from slime, from dew, and from the skins of old eels or of snakes. The statement that they come from horse-hairs is familiar to many country boys, and the origin of this belief is due simply to the fact that there are certain aquatic worms, known under the generic name Gordius, which are elongated and apparently smooth like the eel, and which may be found in the same waters. It was one of the ideas of the Greek to attribute their paternity, as of many other doubtful offspring, to the convenient Jupiter. The statement that they are viviparous has arisen from two causes: one the existence of intestinal worms, and the other from the confusion of the eel with an elongated and consequently eel-like but otherwise very different form, the Zoarces viviparus. The Zoarces is indeed, in Germany as well as in the Scandinavian countries, generally known as the Aal-mutter, or eel-mother, and thus in its name perpetuates the fancy. Even where eels are to be found in extreme abundance, and where they are the objects of a special culture, like erroneous opinions prevail. Thus, according to Jacoby, about the lagoon of Comacchio there is an 'ineradicable belief among the fishermen that the eel is born of other fishes; they point to special differences in color and especially in the common mullet, Mugil cephalus, as the causes of variation in color and form among eels. It is a very ancient belief, widely prevalent to the present day, that eels pair with water-snakes. In Sardinia the fishermen cling to the belief that a certain beetle, the so-called water-beetle, Dytiscus ræselii, is the progenitor of eels, and they therefore call this "mother of eels."' The assignment of such maternity to the water-beetle is doubtless due to the detection of the hair-worm, or Gordius, in the insect by sharp-sighted but unscientific observers, and, inasmuch as the beetle inhabits the same waters as the eel, a very illogical deduction has led to connect the two together.
"All such beliefs as have been thus recounted are due to the inconspicuous nature of the generative organs in eels found in fresh waters and at most seasons—a characteristic which is in strong contrast to the development of corresponding parts in fishes generally. Nevertheless the ovaries of the eel were discovered, as long ago as 1707, by Dr. Sancassini of Comacchio, and described by the celebrated Valisneri (after whom the plant Valisneria was named) in 1710, again by Mondini in 1777, and almost contemporaneously by O. J. Müller of Denmark. Later the illustrious Rathke (in 1824, 1838, and 1850) and also Hornbaum-Hornschuch published the results of special investigations, and figured the eggs. But it was only in 1873 (after several futile endeavors by others) that the male organ of the eel was recognized, also by an Italian naturalist, Dr. Syrski, in small individuals of the species, and a previous idea that the eel was hermaphroditic thereby dispelled. The sexual differences are correlated with external ones, and generally the males and females, when adult, can be told apart. Jacoby testifies that he examined large numbers with a view to solve this question. The most important differences relate to (1) size; (2) form of the snout; (3) color; (4) dorsal fin; and (5) size of the eyes. (1) The males rarely attain a length of more than seventeen to nineteen inches, while adult females are generally much larger; (2) the snout in the male is attenuated and rather pointed, while in the female it is comparatively broad and blunt; (3) the male is of a deep darkish green, or often a deep black with a shining luster and a whitish belly, while the female has a clearer color, usually of a greenish hue on the back and yellowish on the belly; (4) the dorsal fin is lower and less developed in the male than in the female; and (5) the eye of the male is large and that of the female, as a rule, comparatively small. These characters, however, do not always hold good. Jacoby remarked that 'special reference having been paid to the height and narrowness of the dorsal fin, much success has been met with in picking out, in the fish-market of Trieste, the eels which possessed the organ of Syrski (that is, the male organ); absolute certainty, however, in recognizing them cannot be guaranteed. If one is searching among living eels with no characters in mind,—with the exception of the first, that of length,—he will find in every ten eels, on an average, eight females and two with the supposed male organ; but if the selection is made with a careful reference to all these marks of difference, the proportion changes, and out of every ten examples about eight will be found with the supposed male organ.'
"According to Herr Benecke, 'it may be assumed with the greatest safety that the eel lays its eggs like most other fish, and that, like the lamprey, it spawns only once and then dies. All the eggs of a female show the same degree of maturity, while in the fish which spawn every year, besides the large eggs which are ready to be deposited at the next spawning period, there exist very many of much smaller size, which are destined to mature hereafter and be deposited in other years. It is very hard to understand how young eels could find room in the body of their mother if they were retained until they had gained any considerable size. The eel embryo can live and grow for a long time supported by the little yolk, but, when this is done, it can only obtain food outside of the body of its mother. The following circumstances lead us to believe that the spawning of the eel takes place only in the sea: (1) that the male eel is found only in the sea or brackish water, while female eels yearly undertake a pilgrimage from the inland waters to the sea, a circumstance which has been known since the time of Aristotle, and upon the knowledge of which the principal capture of eels by the use of fixed apparatus is dependent; (2) that the young eels, with the greatest regularity, ascend from the sea into the rivers and lakes.'"
All statements in opposition to this theory are untenable, since the young eels never find their way into landlocked ponds in the course of their wanderings, while eels planted in such isolated bodies of water thrive and grow rapidly, but never increase in numbers. Another still more convincing argument is the fact that in lakes which formerly contained many eels, but which, by the erection of impassable weirs, have been cut off from the sea, the supply of eels has diminished, and after a time only scattering individuals, old and of great size, are taken in them. An instance of this sort occurred in Lake Muskengorf in West Prussia. If an instance of the reproduction of the eel in fresh water could be found, such occurrences as these would be quite inexplicable.
In the upper stretches of long rivers the migration of the eels begins in April or in May; in their lower stretches and shorter streams, later in the season. In all running waters the eel-fishery depends upon the downward migrations; the eels press up the streams with occasional halts, remaining here and there for short periods, but always make their way above. They appear to make the most progress during dark nights, when the water is troubled and stormy, for at this time they are captured in the greatest numbers. It is probable that after the eels have once returned to the sea and there deposited their spawn, they never can return into fresh water, but remain there to die. A great migration of grown eels in spring or summer has never been reported, and it appears certain that all the female eels which have once found their way to the sea are lost to the fisherman.
=Food of the Eel.=—Eels, in the words of Mr. W. H. Ballou, are "among the most voracious of carnivorous fishes. They eat most inland fishes, except the garfish and the chub. Investigation of six hundred stomachs by Oswego fishermen showed that the latter bony fish never had a place in their bill of fare. They are particularly fond of game-fishes, and show the delicate taste of a connoisseur in their selection from choice trout, bass, pickerel, and shad. They fear not to attack any object when disposed, and their bite in human flesh shows even a vicious attitude towards man. On their hunting excursions they overturn huge and small stones alike, working for hours if necessary, beneath which they find species of shrimp and crayfish, of which they are exceedingly fond. Of shrimps they devour vast numbers. Their noses are poked into every imaginable hole in their search for food, to the terror of innumerable small fishes."
In the opinion of Mr. Ballou, too, "eels are to the water what the fishhawk is to the air. They are, perhaps, the most powerful and rapid of natatorians. Again, they hide in the mud beneath some log or overhanging rock, and dart out with tremendous fury at the unsuspecting prey. They attack the spawn of other fishes open-mouthed, and are even said to suck the eggs from an impaled female. They fearlessly and rapidly dive head-foremost in the mud, disappearing from view in the twinkling of a star. They are owl-like in their habits, committing many of their depredations at night.
"No fish is yet reported to utilize a full-grown eel as food. Pickerel, garfish, and bass, which are particularly numerous in these lakes, are supposed to literally devour the young fry. Mr. Sawyer describes the operation of the pickerel darting through a long column of young eels open-mouthed and devouring vast numbers of them."
=Larva of the Eel.=—The translucent band-shaped larva of the common eel has been very recently identified and described by Dr. Eigenmann. It is probable that all true eels, Enchelycephali, pass through a band-shaped or leptocephalous stage, as is the case with Albula and other Isospondyli. In the continued growth the body becomes firmer, and at the same time much shorter and thicker, gradually assuming the normal form of the species in question.
In a recent paper Dr. Carl H. Eigenmann has very fully reviewed the life-history of the eel. The common species live in fresh waters, migrating to the sea in the winter. They deposit in deep water minute eggs that float at the surface. The next year they develop into the band-shaped larva. The young eels enter the streams two years after their parents drop down to the sea. It is doubtful whether eels breed in fresh water. The male eel is much smaller than the female.
The eel is an excellent food-fish, the flesh being tender and oily, of agreeable flavor, better than that of any of its relatives. Eels often reach a large size, old individuals of five or six feet in length being sometimes taken.
=Species of Eels.=—The different species are very closely related. Not more than four or five of them are sharply defined, and these mostly in the South Seas and in the East Indies. The three abundant species of the north temperate zone, Anguilla anguilla of Europe, Anguilla chrisypa of the eastern United States, and Anguilla japonica of Japan, are scarcely distinguishable. In color, size, form, and value as food they are all alike.
Fossil species referred to the Anguillidæ are known from the early Tertiary. Anguilla leptoptera occurs in the Eocene of Monte Bolea, and Anguilla elegans in the Miocene of Œningen in Baden. Other fossil eels seem to belong to the Nettastomidæ and Myridæ.
=Pug-nosed Eels.=—Allied to the true eel is the pug-nosed eel, Simenchelys parasiticus, constituting the family of Simenchelyidæ. This species is scaled like a true eel, has a short, blunt nose, and burrows its way into the bodies of halibut and other large fishes. It has been found in Newfoundland and Madeira. Another family possessing rudimentary scales is that of the Synaphobranchidæ, slender eels of the ocean depths, widely distributed. In these forms the gill-openings are confluent. Synaphobranchus pinnatus is the best-known species.
=Conger-eels.=—The Leptocephalidæ, or conger-eels, are very similar to the fresh-water eels, but are without scales and with a somewhat different mouth, the dorsal beginning nearer to the head.
The principal genus is Leptocephalus, including the common conger-eel (Leptocephalus conger) of eastern America and Europe and numerous very similar species in the tropics of both continents. These fishes are strictly marine and, reaching the length of five or six feet, are much valued as food. The eggs are much larger than those of the eel and are produced in great numbers, so that the female almost bursts with their numbers. Dr. Hermes calculated that 3,300,000 were laid by one female in an aquarium.
These eggs hatch out into transparent band-like larva, with very small heads formerly known as Leptocephalus, an ancient name which is now taken for the genus of congers, having been first used for the larva of the common conger-eel. The loose watery tissues of these "ghost-fishes" grow more and more compact and they are finally transformed into young congers.
The Murænesocidæ are large eels remarkable for their strong knife-like teeth. Murænesox savanna occurs in the West Indies and in the Mediterranean, Murænesox cinereus in Japan, and Murænesox coniceps on the west coast of Mexico, all large and fierce, with teeth like shears. The Myridæ are small and worm-like eels closely allied to the congers, having the tail surrounded by a fin, but the nostrils labial. Myrus myrus is found in the Mediterranean. Species of Eomyrus, Rhynchorhinus, and Paranguilla apparently allied to Myrus occur in the Eocene. Other related families, mostly rare or living in the deep seas, are the Ilyophidæ, Heterocongridæ, and Dysommidæ.
=The Snake-eels.=—Most varied of the families of eels is the Ophichthyidæ, snake-like eels recognizable by the form of the tail, which protrudes beyond the fins. Of the many genera found in tropical waters several are remarkable for the sharply defined coloration, suggesting that of the snake. Characteristic species are Chlevastes colubrinus and Leiuranus semicinctus, two beautifully banded species of Polynesia, living in the same holes in the reefs and colored in the same fashion. Another is Callechelys melanotænia. The commonest species on the Atlantic coast is the plainly colored Ophichthus gomesi.
In the genus Sphagebranchus, very slender eels of the reefs, the fins are almost wanting.
Allied to the Congers is the small family of duck-billed eels (Nettastomidæ) inhabiting moderate depths of the sea. Nettastoma bolcense occurs in the Eocene of Monte Bolca. The produced snout forms a transition to the really extraordinary type of thread-eels or snipe-eels (Nemichthyidæ), of which numerous genera and species live in the oceanic depths. In Nemichthys the long, very slender, needle-like jaws are each curved backward so that the mouth cannot by any possibility be shut. The body is excessively slender and the fish swims with swift undulations, often near the surface, and when seen is usually taken for a snake. The best-known species is Nemichthys scolopaceus of the Atlantic and Pacific. Nemichthys avocetta, very much like it, has been twice taken in Puget Sound.
=Suborder Colocephali, or Morays.=—In the suborder Colocephali (κολός, deficient; κεφαλή, head) the palatopterygoid arch and the membrane-bones generally are very rudimentary. The skull is thus very narrow, the gill-structures are not well developed, and in the chief family there are no pectoral fins. This group is very closely related to the Enchelycephali, from which it is probably derived.
In the great family of morays (Murænidæ) the teeth are often very highly developed. The muscles are always very strong and the spines bite savagely, a live moray being often able to drive men out of a boat. The skin is thick and leathery, and the coloration is highly specialized, the pattern of color being often elaborate and brilliant. In Echidna zebra for example the body is wine-brown, with cross-stripes of golden yellow. In Muræna each nostril has a barbel. Muræna helena, the oldest moray known, is found in Europe. In Gymnothorax, the largest genus, only the anterior nostrils are thus provided. Gymnothorax mordax of California is a large food-fish, as are also the brown Gymnothorax funebris and the spotted Gymnothorax moringa in the West Indies. These and many other species may coil themselves in crevices in the reefs, whence they strike out at their prey like snakes, taking perhaps the head of a duck or the finger of a man.
In many of the morays the jaws are so curved and the mouth so filled with knife-like teeth that the jaws cannot be closed. This fact, however, renders no assistance to their prey, as the teeth are adapted for holding as well as for cutting.
In Enchelynassa bleekeri, a huge wine-colored eel of the South Seas, the teeth are larger than in any other species. Evenchelys (macrurus) is remarkable for its extraordinary length of tail, Echidna for its blunt teeth, and Scuticaria, Uropterygius, and Channomuræna for the almost complete absence of fins. In Anarchias (allardicei; knighti), the anal fin is absent. The flesh of the morays is rather agreeable in taste, but usually oily and not readily digestible, less wholesome than that of the true eels.
The Myrocongridæ are small morays with developed pectoral fins. The species are few and little known.
=Family Moringuidæ.=—Structurally one of the most peculiar of the groups of eels is the small family of Moringuidæ of the East and West Indies. In these very slender, almost worm-like fishes the heart is placed very far behind the gills and the tail is very short. The fins are very little developed, and some forms, as Gordiichthys irretitus of the Gulf of Mexico, the body as slender as a whiplash, possess a very great number of vertebræ. Moringua hawaiiensis occurs in Hawaii, M. edwardsi in the Bahamas. This family probably belongs with the morays to the group of Colocephali, although its real relationships are not wholly certain.
=Order Carencheli, the Long-necked Eels.=—Certain offshoots from the Apodes so widely diverging in structure that they must apparently be considered as distinct orders occur sparingly in the deep seas. One of these, Derichthys serpentinus, the long-necked eel, constitutes the sole known species of the suborder Carencheli (καρά, head; ἔγχελυς, eel). In this group the premaxillaries and maxillaries are present as in ordinary fishes, but united by suture and soldered to the cranium. As in true eels, the shoulder-girdle is remote from the skull. The head is set on a snake-like neck. The single species representing the family Derichthyidæ was found in the abysmal depths of the Gulf Stream.
=Order Lyomeri, or Gulpers.=—Still more aberrent and in many respects extraordinary are the eels of the order or suborder Lyomeri (λυός, loose; μέρος, part), known as "Gulpers." These are degenerate forms, possibly degraded from some conger-like type, but characterized by an extreme looseness of structure unique among fishes. The gill-arches are reduced to five small bars of bone, not attached to the skull, the palatopterygoid arch is wholly wanting, the premaxillaries are wanting, as in all true eels, and the maxillaries loosely joined to the skull. The symplectic bone is wanting, and the lower jaw is so hinged to the skull that it swings freely in various directions. In place of the lateral line are singular appendages. Dr. Gill says of these fishes: "The entire organization is peculiar to the extent of anomaly, and our old conceptions of the characteristics of a fish require to be modified in the light of our knowledge of such strange beings." Special features are the extraordinary size of the mouth, which has a cavity larger than that of the rest of the body, the insertion of the very small eye at the tip of the snout, and the relative length of the tail. The whole substance is excessively fragile as usual with animals living in great depths and the color is jet black. Three species have been described, and these have been placed in two families, Saccopharyngidæ, with the trunk (gill-opening to the vent) much longer than the head, and Eurypharyngidæ, with the trunk very short, much shorter than the head. The best-known species is the pelican eel (Eurypharynx pelacanoides), of the coast of Morocco, described by Vaillant in 1882. Gastrostomus bairdi, very much like it, occurs in the great depths under the Gulf Stream. So fragile and so easily distorted are these fishes that it is possible that all three are really the same species, for which the oldest name would be Saccopharynx ampullaceus. Of this form four specimens have been taken in the Atlantic, one of them six feet long, carried to the surface through having swallowed fishes too large to be controlled. To be carried above its depth in a struggle with its prey is one of the greatest dangers to which the abysmal fishes are subject.
=Order Heteromi.=—The order of Heteromi (ἑτερός, different; ὤμος, shoulder), or spiny eels, may be here noticed for want of a better place, as its affinities are very uncertain. Some writers have regarded it as allied to the eels; some have placed it among the Ganoids. Others have found affinities with the sticklebacks, and still others with the singular fresh-water fishes called Mastacembelus. The Heteromi agree with the eels, as well as with Mastacembelus, in having the scapular arch separate from the cranium. Unlike all the true eels, most of the species have true dorsal and anal spines, as in the Percesoces and Hemibranchii. The ventral fins, when present, are abdominal and each with several spines in front, a character not found among the Acanthopteri. There is no mesocoracoid.
The air-bladder has a duct, and the coracoids, much as in the Xenomi, are reduced to a single lamellar imperforate plate. The two groups have little else in common, however, and this trait is possibly primitive in both cases, more likely to have arisen through independent degeneration. The separation of the shoulder-girdle doubtless indicates no affinity with the eels, as the bones of the jaws are quite normal. Two families are known, both from the deep sea, besides an extinct family in which spines are not developed.
The Notacanthidæ are elongate, compressed, ending in a band-shaped, tapering tail; the back has numerous free spines and few or no soft rays, and the mouth is normal, provided with teeth. The species of Notacanthus are few and scantily preserved. Those of Macdonaldia are more abundant. Macdonaldia challengeri is from the North Pacific, being once taken off Tokio. The extinct family of Protonotacanthidæ differs in the total absence of dorsal spines and fin-rays; the single species, Pronotocanthus sahel-almæ, originally described as a primitive eel, occurs in the Cretaceous of Mount Lebanon.
The Lipogenyidæ have a round, sucker-like mouth, with imperfect lower jaw, but are otherwise similar. Lipogenys gilli was dredged in the Gulf Stream.
Dr. Boulenger has recently extended the group of Heteromi by the addition of the Dercetidæ, Halosauridæ (Lyopomi), and the Fierasferidæ. We can hardly suppose that all these forms are really allied to Notacanthus.
VIII. SERIES OSTARIOPHYSI
=OSTARIOPHYSI.=—A large group of orders, certainly of common descent, may be brought together under the general name of Ostariophysi (ὀσταρίον, a small bone; θυσός, inflated). These are in many ways allied to the Isospondyli, but they have undergone great changes of structure, some of the species being highly specialized, others variously degenerate. A chief character is shared by all the species. The anterior vertebræ are enlarged, interlocked, considerably modified, and through them a series of small bones connect the air-bladder with the ear. The air-bladder thus becomes apparently an organ of hearing through a form of connection which is lost in all the higher fishes.
In all the members of this group excepting perhaps the degraded eel-like forms called Gymnonoti, the mesocoracoid arch persists, a trait found in all the living types of Ganoids, as well as in the Teleost order of Isospondyli. Other traits of the Ostariophysan fishes are shared by the Isospondyli (herring, salmon) and other soft-rayed fishes. The air-bladder is large, but not cellular. It leads through life by an open duct to the œsophagus. The ventral fins are abdominal in position. The pectorals are inserted low. A mesocoracoid arch is developed on the inner side of the shoulder-girdle. (See Fig. 119.) There are no spines on the fins, except in many cases a single one, a modified soft ray at front of dorsal or pectoral. The scales, if present, are cycloid or replaced by bony plates.
Many of the species have an armature much like that of the sturgeon, but here the resemblance ends, the bony plates in the two cases being without doubt independently evolved. According to Cope, the affinities of the catfishes to the sturgeon are "seen in the absence of symplectic, the rudimentary maxillary bone, and, as observed by Parker, in the interclavicles. There is also a superficial resemblance in the dermal bones." But it is not likely that any real affinity exists.
The sturgeons lack the characteristic auditory ossicles, or "Weberian apparatus," which the catfishes possess in common with the carp family, the Characins, and the Gymnonoti. These orders must at least have a common origin, although this origin is obscure, and fossil remains give little help to the solution of the problem. Probably the ancestors of the Ostariophysi are to be found among the allies of the Osteoglossidæ. Gill has called attention to the resemblance of Erythrinus to Amia. In any event, all the Ostariophysi must be considered together, as it is not conceivable that so complex a structure as the Weberian apparatus should have been more than once independently evolved. The branchiostegals, numerous among the Isospondyli, are mostly few among the Ostariophysi.
To the Ostariophysi belong the vast majority of the fresh-water fishes of the world. Their primitive structure is shown in many ways; among others by the large number of vertebræ instead of the usual twenty-four among the more highly specialized families of fishes. We may group the Ostariophysi under four orders: Heterognathi, Eventognathi (Plectospondyli), Nematognathi, and Gymnonoti.
=The Heterognathi.=—Of these the order of Heterognathi seems to be the most primitive, but in some ways the most highly developed, showing fewer traits of degeneration than any of the others. The presence of the adipose fin in this group and in the catfishes seems to indicate some sort of real affinity with the salmon-like forms, although there has been great change in other regards.
The order Heterognathi, or Characini (ἕτερος, different; γνάθος, jaw), contains those Ostariophysi which retain the mesocoracoid and are not eel-like, and which have the lower pharyngeals developed as in ordinary fishes. In most cases an adipose fin is present and there are strong teeth in the jaws. There are no pseudobranchiæ, and, as in the Cyprinidæ, usually but three branchiostegals. The Characidæ constitute the majority of the fresh-water fishes in those regions which have neither Cyprinidæ nor Salmonidæ. Nearly four hundred species are known from the rivers of South America and Africa. A single species, Tetragonopterus argentatus, extends its range northward to the Rio Grande in Texas. None are found in Asia, Europe, or, with this single exception, in the United States. Most of them are small fishes with deep bodies and very sharp, serrated, incisor-like teeth. Some are as innocuous as minnows, which they very much resemble, but others are extremely voracious and destructive in the highest degree. Of the caribe, belonging to the genus Serrasalmo, known by its serrated belly, Dr. Günther observes:
"Their voracity, fearlessness and number render them a perfect pest in many rivers of tropical America. In all the teeth are strong, short, sharp, sometimes lobed incisors, arranged in one or more series; by means of them they cut off a mouthful of flesh as with a pair of scissors; and any animal falling into the water where these fish abound is immediately attacked and cut to pieces in an incredibly short time. They assail persons entering the water, inflicting dangerous wounds before the victims are able to make their escape. In some localities it is scarcely possible to catch fishes with the hook and line, as the fish hooked is immediately attacked by the 'caribe' (as these fish are called), and torn to pieces before it can be withdrawn from the water. The caribes themselves are rarely hooked, as they snap the hook or cut the line. The smell of blood is said to attract at once thousands of these fishes to the spot."
Two families of Heterognathi are recognized: the Erythrinidæ, which lack the adipose fin, and the Characidæ, in which this fin is developed. The Erythrinidæ are large pike-like fishes of the South American rivers, robust and tenacious of life, with large mouths armed with strong unequal teeth. The best-known species is the Trahira (Hoplias malabaricus).
Among the Characidæ, Serrasalmo has been already noticed. Citharinus in Africa has very few teeth, and Curimatus in South America none at all. Nannocharax in Africa is composed of very diminutive fishes, Hydrocyon exceedingly voracious ones, reaching a length of four feet, with savage teeth. Many of the species are allies of Tetragonopterus, small, silvery, bream-like fishes with flat bodies and serrated incisor teeth. Most of these are American. A related genus is Brycon, found in the streams about the Isthmus of Panama.
Extinct Characins are very rare. Two species from the Tertiary lignite of São Paulo, Brazil, have been referred to Tetragonopterus—T. avus and T. ligniticus.
=The Eventognathi.=—The Eventognathi (ἔυ, well; ἔν, within; γνάθος, jaw) are characterized by the absence of teeth in the jaws and by the high degree of specialization of the lower pharyngeals, which are scythe-shaped and in typical forms are armed with a relatively small number of highly specialized teeth of peculiar shape and arranged in one, two, or three rows. In all the species the gill-openings are restricted to the sides; there is no adipose fin, and the broad, flat branchiostegals are but three in number. In all the species the scales, if present, are cycloid, and the ventral fins, of course, abdominal. The modification of the four anterior vertebræ and their connection with the air bladder are essentially as seen in the catfishes.
The name Plectospondyli is often used for this group (πλεκτός, interwoven; σπόνδυλος, vertebra), but that term originally included the Characins as well.
=The Cyprinidæ.=—The chief family of the Eventognathi and the largest of all the families of fishes is that of Cyprinidæ, comprising 200 genera and over 2000 species, found throughout the north temperate zone but not extending to the Arctic Circle on the north, nor much beyond the Tropic of Cancer on the south. In this family belong all the fishes known as carp, dace, chub, roach, bleak, minnow, bream, and shiner. The essential character of the family lies in the presence of one, two, or three rows of highly specialized teeth on the lower pharyngeals, the main row containing 4, 5, 6, or 7 teeth, the others 1 to 3. The teeth of the main row differ in form according to the food of the fish. They may be coarse and blunt, molar-like in those which feed on shells; they may be hooked at tip in those which eat smaller fishes; they may be serrated or not; they may have an excavated "grinding surface," which is most developed in the species which feed on mud and have long intestines. In the Cyprinidæ, or carp family, the barbels are small or wanting, the head is naked, the caudal fin forked, the mouth is toothless and without sucking lips, and the premaxillaries form its entire margin. With a few exceptions the Cyprinidæ are small and feeble fishes. They form most of the food of the predatory river fishes, and their great abundance in competition with these is due to their fecundity and their insignificance. They spawn profusely and find everywhere an abundance of food. Often they check the increase of predatory fish by the destruction of their eggs.
In many of the genera the breeding color of the males is very brilliant, rendering these little creatures for a time the most beautifully colored of fishes. In spring and early summer the fins, sides, and head in the males are often charged with pigment, the prevailing color of which is rosy, though often satin-white, orange, crimson, yellow, greenish, or jet black. Among American genera Chrosomus, Notropis, and Rhinichthys are most highly colored. Rhodeus, Rutilus, and Zacco in the Old World are also often very brilliant.
In very many species, especially in America, the male in the breeding season is often more or less covered with small, grayish tubercles or pearly bodies, outgrowths of the epidermis. These are most numerous on the head and fall off after the breeding season. They are most developed in Campostoma.
The Cyprinidæ are little valued as food-fishes. The carp, largely domesticated in small ponds for food, is coarse and tasteless. Most of the others are flavorless and full of small bones. One species, Opsariichthys uncirostris, of Japan is an exception in this regard, being a fish of very delicate flavor.
In America 225 species of Cyprinidæ are known. One hundred of these are now usually held to form the single genus Notropis. This includes the smaller and weaker species, from two to seven inches in length, characterized by the loss, mostly through degeneration, of special peculiarities of mouth, fins, and teeth. These have no barbels and never more than four teeth in the main row. Few, if any, Asiatic species have so small a number, and in most of these the maxillary still retains its rudimentary barbel. But one American genus (Orthodon) has more than five teeth in the main row and none have more than two rows or more than two teeth in the lower row. By these and other peculiarities it would seem that the American species are at once less primitive and less complex than the Old World forms. There is some evidence that the group is derived from Asia through western America, the Pacific Coast forms being much nearer the Old World types than the forms inhabiting the Mississippi Valley. Not many Cyprinidæ are found in Mexico, none in Cuba, South America, Australia, Africa, or the islands to the eastward of Borneo. Many species are very widely distributed, many others extremely local. In the genus Notropis, each river basin in the Southern States has its series of different and mostly highly colored species. The presence of Notropis niveus in the Neuse, Notropis pyrrhomelas in the Santee, Notropis zonistius in the Chattahoochee, Notropis callistius, trichroistius, and stigmaturus in the Alabama, Notropis whipplei in the Mississippi, Notropis galacturus in the Tennessee, and Notropis cercostigma in the Sabine forms an instructive series in this regard. These fishes and the darters (Etheostominæ) are, among American fishes, the groups best suited for the study of local problems in distribution.
=Species of Dace and Shiner.=—Noteworthy species in other genera are the following:
Largest and best known of the species of Notropis is the familiar shiner or redfin, Notropis cornutus, found in almost every brook throughout the region east of the Missouri River.
Campostoma anomalum, the stone-roller, has the very long intestines six times the length of its body, arranged in fifteen coils around the air-bladder. This species feeds on mud and spawns in little brooks, swarming in early spring throughout the Mississippi Valley, and is notable for its nuptial tubercles and the black and orange fins.
In the negro-chub, Exoglossum maxillingua of the Pennsylvanian district, the rami of the lower jaw are united for their whole length, looking like a projecting tongue.
The fallfish, Semotilus corporalis, is the largest chub of the Eastern rivers, 18 inches long, living in swift, clear rivers. It is a soft fish, and according to Thoreau "it tastes like brown paper salted" when it is cooked. Close to this is the horned dace, Semotilus atromaculatus, and the horny head, Hybopsis kentuckiensis, both among the most widely distributed of our river fishes. These are all allied to the gudgeon (Gobio gobio), a common boys' fish of the rivers of Europe, and much sought by anglers who can get nothing better. The bream, Abramis, represented by numerous species in Europe, has a deep compressed body and a very long anal fin. It is also well represented in America, the golden shiner, common in Eastern and Southern streams, being Abramis chrysoleucus. The bleak of Europe (Alburnus alburnus) is a "shiner" close to some of our species of Notropis, while the minnow of Europe, Phoxinus phoxinus, resembles our gorgeously colored Chrosomus erythrogaster. Other European forms are the roach (Rutilus rutilus), the chub (Leuciscus cephalus), the dace (Leuciscus leuciscus), the id (Idus idus), the redeye (Scardinius erythropthalmus), and the tench (Tinca tinca). The tench is the largest of the European species, and its virtues with those of its more or less insignificant allies are set forth in the pages of Izaak Walton. All of these receive more attention from anglers in England than their relatives receive in America. All the American Cyprinidæ are ranked as "boys' fish," and those who seek the trout or black bass or even the perch or crappie will not notice them. Thoreau speaks of the boy who treasures the yellow perch as a real fish: "So many unquestionable fish he counts, then so many chubs which he counts, then throws away."
=Chubs of the Pacific Slope.=—In the Western waters are numerous genera, some of the species reaching a large size. The species of squawfish (Ptychocheilus lucius in the Colorado, Ptychocheilus grandis in the Sacramento, and Ptychocheilus oregonensis in the Columbia) reach a length of 4 or 5 feet or even more. These fishes are long and slender, with large toothless mouths and the aspect of a pike.
Allied to these are the "hard tails" (Gila elegans and Gila robusta) of the Colorado Basin, strange-looking fishes scarcely eatable, with lean bodies, flat heads, and expanded tails. The split-tail, Pogonichthys macrolepidotus, is found in the Sacramento.
In the chisel-mouth, Acrocheilus alutaceus, of the Columbia the lips have a hard cutting edge. In Meda, very small fishes of the Colorado Basin, the dorsal has a compound spine of peculiar structure. Many of the species of Western waters belong to the genus Leuciscus, which includes also many species of Asia and Europe. The common Japanese dace (Leuciscus hakuensis) is often found out in the sea, but, in general, Cyprinidæ are only found in fresh waters. The genus of barbels (Barbus) contains many large species in Europe and Asia. In these the barbel is better developed than in most other genera, a character which seems to indicate a primitive organization. Barbus mosal of the mountains of India is said to reach a length of more than six feet and to have "scales as large as the palm of the hand."
=The Carp and Goldfish.=—In the American and European Cyprinidæ the dorsal fin is few-rayed, but in many Asiatic species it is longer, having 15 to 20 rays and is often preceded by a serrated spine like that of a catfish. Of the species with long dorsal the one most celebrated is the carp (Cyprinus carpio). This fish is a native of the rivers of China, where it has been domesticated for centuries. Nearly three hundred years ago it was brought to northern Europe, where it has multiplied in domestication and become naturalized in many streams and ponds. Of late years the cultivation of the carp has attracted much attention in America. It has been generally satisfactory where the nature of the fish is understood and where expectations have not been too high.
The carp is a dull and sluggish fish, preferring shaded, tranquil, and weedy waters with muddy bottoms. Its food consists of water insects and other small animals, and vegetable matter, such as the leaves of aquatic plants. They can be fed on much the same things as pigs and chickens, and they bear much the same relation to trout and bass that pigs and chickens do to wild game and game-birds. The carp is a very hardy fish, grows rapidly, and has immense fecundity, 700,000 eggs having been found in the ovaries of a single individual. It reaches sometimes a weight of 30 to 40 pounds. As a food-fish the carp cannot be said to hold a high place. It is tolerated in the absence of better fish.
The carp, either native or in domestication, has many enemies. In America, catfish, sunfish, and pike prey upon its eggs or its young, as well as water-snakes, turtles, kingfishes, crayfishes, and many other creatures which live about our ponds and in sluggish streams. In domestication numerous varieties of carp have been formed, the "leather-carp" (Lederkarpfen) being scaleless, others, "mirror-carp" (Spiegelkarpfen), having rows of large scales only along the lateral line or the bases of the fins.
Closely allied to the carp is the goldfish (Carassius auratus). This is also a common Chinese fish introduced in domestication into Europe and America. The golden-yellow color is found only in domesticated specimens, and is retained by artificial selection. The native goldfish is olivaceous in color, and where the species has become naturalized (as in the Potomac River, where it has escaped from fountains in Washington) it reverts to its natural greenish hue. The same change occurs in the rivers of Japan. The goldfish is valued solely for its bright colors as an ornamental fish. It has no beauty of form nor any interesting habits, and many of our native fishes (Percidæ, Cyprinidæ) far excel it in attractiveness as aquarium fishes. Unfortunately they are less hardy. Many varieties and monstrosities of the goldfish have been produced by domestication.
=The Catostomidæ.=—The suckers, or Catostomidæ, are an offshoot from the Cyprinidæ, differing chiefly in the structure of the mouth and of the lower pharyngeal bones. The border of the mouth above is formed mesially by the small premaxillaries and laterally by the maxillaries. The teeth of the lower pharyngeals are small and very numerous, arranged in one series like the teeth of a comb. The lips are usually thick and fleshy, and the dorsal fin is more or less elongate (its rays eleven to fifty in number), characters which distinguish the suckers from the American Cyprinidæ generally, but not from those of the Old World.
About sixty species of suckers are known, all of them found in the rivers of North America except two, which have been recorded on rather uncertain authority from Siberia and China. Only two or three of the species extend their range south of the Tropic of Cancer into Mexico or Central America, and none occur in Cuba nor in any of the neighboring islands. The majority of the genera are restricted to the region east of the Rocky Mountains, although species of Catostomus, Chasmistes, Deltistes, Xyrauchen, and Pantosteus are found in abundance in the Great Basin and the Pacific slope.
In size the suckers range from six inches in length to about three feet. As food-fishes they are held in low esteem, the flesh of all being flavorless and excessively full of small bones. Most of them are sluggish fishes; they inhabit all sorts of streams, lakes, and ponds, but even when in mountain brooks they gather in the eddies and places of greatest depth and least current. They feed on insects and small aquatic animals, and also on mud, taking in their food by suction. They are not very tenacious of life. Most of the species swarm in the spring in shallow waters. In the spawning season they migrate up smaller streams than those otherwise inhabited by them. The large species move from the large rivers into smaller ones; the small brook species go into smaller brooks. In some cases the males in spring develop black or red pigment on the body or fins, and in many cases tubercles similar to those found in the Cyprinidæ appear on the head, body, and anal and caudal fins.
The buffalo-fishes and carp-suckers, constituting the genera Ictiobus and Carpiodes, are the largest of the Catostomidæ, and bear a considerable resemblance to the carp. They have the dorsal fin many rayed and the scales large and coarse. They abound in the large rivers and lakes between the Rocky Mountains and the Alleghanies, one species being found in Central America and a species of a closely related genus (Myxocyprinus asiaticus) being reported from eastern Asia. They rarely ascend the smaller rivers except for the purpose of spawning. Although so abundant in the Mississippi Valley as to be of importance commercially, they are very inferior as food-fishes, being coarse and bony. The genus _Cycleptu_s contains the black-horse, or Missouri sucker, a peculiar species with a small head, elongate body, and jet-black coloration, which comes up the smaller rivers tributary to the Mississippi and Ohio in large numbers in the spring. Most of the other suckers belong to the genera Catostomus and Moxostoma, the latter with the large-toothed Placopharynx being known, from the red color of the fins, as red-horse, the former as sucker. Some of the species are very widely distributed, two of them (Catostomus commersoni, Erimyzon sucetta) being found in almost every stream east of the Rocky Mountains and Catostomus catostomus throughout Canada to the Arctic Sea. The most peculiar of the suckers in appearance is the harelip sucker (Quassilabia lacera) of the Western rivers. Very singular in form is the humpback or razor-back sucker of the Colorado, Xyrauchen cypho.
=Fossil Cyprinidæ.=—Fossil Cyprinidæ, closely related to existing forms, are found in abundance in fresh-water deposits of the Tertiary, but rarely if ever earlier than the Miocene. Cyprinus priscus occurs in the Miocene of Germany, perhaps showing that Germany was the original home of the so-called "German carp," afterwards actually imported to Germany from China. Some specimens referred to Barbus, Tinca, Rhodeus, Aspius, and Gobio are found in regions now inhabited by these genera, and many species are referred to the great genus Leuciscus, Leuciscus œningensis from the Miocene of Germany being perhaps the best known. Several species of Leuciscus or related genera are found in the Rocky Mountain region. Among these is the recently described Leuciscus turneri.
Fossil Catostomidæ are very few and chiefly referred to the genus Amyzon, supposed to be allied to Erimyzon, but with a longer dorsal. Amyzon commune and other species are found in the Rocky Mountains, especially in the Miocene of the South Park in Colorado and the Eocene of Wyoming. Two or three species of Catostomus, known by their skulls, are found in the Pliocene of Idaho.
=The Loaches.=—The Cobitidæ, or loaches, are small fishes, all less than a foot in length, inhabiting streams and ponds of Europe and Asia. In structure they are not very different from minnows, but they are rather eel-like in form, and the numerous long barbels about the mouth strongly suggest affinity with the catfishes. The scales are small, the pharyngeal teeth few, and the air-bladder, as in most small catfishes, enclosed in a capsule. The loaches are all bottom fishes of dark colors, tenacious of life, feeding on insects and worms. The species often bury themselves in mud and sand. They lie quiet on the bottom and move very quickly when disturbed much after the manner of darters and gobies. Species of Cobitis and Misgurnus are widely distributed from England to Japan. Nemachilus barbatulus is the commonest European species. Cobitis tænia is found, almost unchanged, from England to the streams of Japan.
Remains of fossil loaches, mostly indistinguishable from Cobitis, occur in the Miocene and more recent rocks.
From ancestors of loaches or other degraded Cyprinidæ we may trace the descent of the catfishes.
The Homalopteridæ are small loaches in the mountain streams of the East Indies. They have no air-bladder and the number of pharyngeal teeth (10 to 16) is greater than in the loaches, carp, or minnows.
IX. THE NEMATOGNATHI, OR CATFISHES
=THE Nematognathi.=—The Nematognathi (νῆμα, thread; γνάθος, jaw), known collectively as catfishes, are recognized at once by the fact that the rudimentary and usually toothless maxillary is developed as the bony base of a long barbel or feeler. Usually other feelers are found around the head, suggesting the "smellers" of a cat. The body is never scaly, being either naked and smooth or else more or less completely mailed with bony plates which often resemble superficially those of a sturgeon. Other distinctive characters are found in the skeleton, notably the absence of the subopercle, but the peculiar development of the maxillary and its barbel with the absence of scales is always distinctive. The symplectic is usually absent, and in some the air-bladder is reduced to a rudiment inclosed in a bony capsule. In almost all cases a stout spine exists in the front of the dorsal fin and in the front of each pectoral fin. This spine, made of modified or coalescent soft rays, is often a strong weapon with serrated edges and capable of inflicting a severe wound. When the fish is alarmed, it sets this spine by a rotary motion in its socket joint. It can then be depressed only by breaking it. By a rotary motion upward and toward the body the spine is again lowered. The wounds made by this spine are often painful, but this fact is due not to a specific poison but to the irregular cut and to the slime of the spine.
In two genera, Noturus and Schilbeodes, a poison-gland exists at the base of the pectoral spine, and the wound gives a sharp pain like the sting of a hornet and almost exactly like the sting of a scorpion-fish. Most of the Nematognathi possess a fleshy or adipose fin behind the dorsal, exactly as in the salmon. In a few cases the adipose fin develops an anterior spine and occasionally supporting rays.
All the Nematognathi are carnivorous bottom feeders, devouring any prey they can swallow. Only a few enter the sea, and they occur in the greatest abundance in the Amazon region. Upward of 1200 species, arranged in 150 genera, are recorded. They vary greatly in size, from two inches to six feet in length. All are regarded as food-fishes, but the species in the sea have very tough and flavorless flesh. Some of the others are extremely delicate, with finely flavored flesh and a grateful absence of small bones.
=Families of Nematognathi.=—According to Dr. Eigenmann's scheme of classification,[11] the most primitive family of Nematognathi is that of Diplomystidæ, characterized by the presence of a well-developed maxillary, as in other soft-rayed fishes. The single species, Diplomystes papillosus, is found in the waters of Chile.
Footnote 11:
A Revision of the South American Nematognathi, 1890, p. 7.
Similar to the Diplomystidæ in all other respects is the great central family of Siluridæ, by far the most numerous and important of all the divisions of Nematognathi.
=The Siluridæ.=—This group has the skin naked or imperfectly mailed, the barbels on the head well developed, the dorsal short, inserted forward, the adipose fin without spine, and the lower pharyngeals separate. All the marine catfishes and most of the fresh-water species belong to this group, and its members, some 700 species, abound in all parts of the world where catfishes are known—"a bloodthirsty and bullying race of rangers inhabiting the river bottoms with ever a lance at rest and ready to do battle with their nearest neighbor."
=The Sea Catfish.=—In the tropical seas are numerous species of catfishes belonging to Tachysurus, Arius, Galeichthys, Felichthys, and other related genera. These are sleek, silvery fishes covered with smooth skin, the head usually with a coat of mail, pierced by a central fontanelle. Some of them reach a considerable size, swarming in sandy bays. None are valued as food, being always tough and coarsely flavored. Sea birds, as the pelican, which devour these catfishes are often destroyed by the sudden erection of the pectoral spines. None of these are found in Europe or in Japan. Of the very many American species the gaff-topsail catfish (Felichthys felis), noted for its very high spines, extends farthest north and is one of the very largest species. This genus has two barbels at the chin. Most others have four. The commonest sea catfish of the Carolina coast is Galeichthys milberti. In Tachysurus the teeth on the palate are rounded, in most of the others they are in villiform bands.
In most or all of the sea catfish the eggs, as large as small peas, are taken into the mouth of the male and there cared for until hatched.
=The Channel Cats.=—In all the rivers of North America east of the Rocky Mountains are found catfishes in great variety. The channel cats, Ictalurus, known most readily by the forked tails, are the largest in size and most valued as food. The technical character of the genus is the backward continuation of the supraoccipital, forming a bony bridge to the base of the dorsal. The great blue cat, Ictalurus furcatus, abounds throughout the large rivers of the Southern States and reaches a weight of 150 pounds or more. It is an excellent food and its firm flesh is readily cut into steaks. In the Great Lakes and northward is a very similar species, also of large size, which has been called Ictalurus lacustris. Another similar species is the willow cat, Ictalurus anguilla. The white channel-cat, Ictalurus punctatus, reaches a much smaller size and abounds on the ripples in clear swift streams of the Southwest, such as the Cumberland, the Alabama, and the Gasconade. It is a very delicate food-fish, with tender white flesh of excellent flavor.
=Horned Pout.=—The genus Ameiurus includes the smaller brown catfish, horned pout, or bullhead. The body is more plump and the caudal fin is usually but not always rounded. The many species are widely diffused, abounding in brooks, lakes, and ponds. Ameiurus nebulosus is the best-known species, ranging from New England to Texas, known in the East as horned pout. It has been successfully introduced into the Sacramento, where it abounds, as well as its congener, Ameiurus catus (see Fig. 229, Vol. I), the white bullhead, brought with it from the Potomac. The latter species has a broader head and concave or notched tail. All the species are good food-fishes. All are extremely tenacious of life, and all are alike valued by the urchin, for they will bite vigorously at any sort of bait. All must be handled with care, for the sharp pectoral spines make an ugly cut, a species of wound from which few boys' hands in the catfish region are often free.
In the caves about Conestoga River in Lancaster County, Pennsylvania, is a partly blind catfish, evidently derived from local species outside the cave. It has been named Gronias nigrilabris.
A few species are found in Mexico, one of them, Ictalurus meridionalis, as far south as Rio Usamacinta on the boundary of Guatemala.
Besides these, a large channel-cat of peculiar dentition, known as Istlarius balsanus, abounds in the basin of Rio Balsas. In Mexico all catfishes are known as Bagre, this species as Bagre de Rio.
The genus Leptops includes the great yellow catfish, or goujon, known at once by the projecting lower jaw. It is a mottled olive and yellow fish of repulsive exterior, and it reaches a very great size. It is, however, a good food-fish.
=The Mad-toms.=—The genera Noturus and Schilbeodes are composed of diminutive catfishes, having the pectoral spine armed at base, with a poison sac which renders its sting extremely painful though not dangerous. The numerous species of this genus, known as "mad-toms" and "stone cats," live among weeds in brooks and sluggish streams. Most of them rarely exceed three inches in length, and their varied colors make them attractive in the aquarium.
=The Old World Catfishes.=—In the catfishes of the Old World and their relatives, the adipose fin is rudimentary or wanting. The chief species found in Europe is the huge sheatfish, or wels, Silurus glanis. This, next to the sturgeon, is the largest river fish in Europe, weighing 300 to 400 pounds. It is not found in England, France, or Italy, but abounds in the Danube. It is a lazy fish, hiding in the mud and thus escaping from nets. It is very voracious, and many stories are told of the contents of its stomach. A small child swallowed whole is recorded from Thorn, and there are still more remarkable stories, but not properly vouched for. The sheatfish is brown in color, naked, sleek, and much like an American Ameiurus save that its tail is much longer and more eel-like. Another large catfish, known to the ancients, but only recently rediscovered by Agassiz and Garman, is Parasilurus aristotelis of the rivers of Greece. In China and Japan is the very similar Namazu, or Japanese catfish, Parasilurus asotus, often found in ponds and used as food. Numerous smaller related catfishes, Porcus (Bagrus), Pseudobagrus, and related genera swarm in the brooks and ponds of the Orient.
In the genus Torpedo (Malapterurus) the dorsal fin is wanting. Torpedo electricus, the electric catfish of the Nile, is a species of much interest to anatomists. The shock is like that of a Leyden jar. The structures concerned are noticed on p. 186, Vol. I. The generic name Torpedo was applied to the electric catfish before its use for the electric ray.
In South America a multitude of genera and species cluster around the genus Pimelodus. Some of them have the snout very long and spatulate. Most of them possess a very long adipose fin. The species are generally small in size and with smooth skin like the North American catfishes. Still other species in great numbers are grouped around the genus Doras. In this group the snout projects, bearing the small mouth at its end, and the lateral line is armed behind with spinous shields. All but one of the genera belong to the Amazon district, Synodontis being found in Africa.
Concerning Doras, Dr. Günther observes: "These fishes have excited attention by their habit of traveling during the dry season from a piece of water about to dry up in quest of a pond of greater capacity. These journeys are occasionally of such a length that the fish spends whole nights on the way, and the bands of scaly travelers are sometimes so large that the Indians who happen to meet them fill many baskets of the prey thus placed in their hands. The Indians suppose that the fish carry a supply of water with them, but they have no special organs and can only do so by closing the gill-openings or by retaining a little water between the plates of their bodies, as Hancock supposes. The same naturalist adds that they make regular nests, in which they cover up their eggs with care and defend them, male and female uniting in this parental duty until the eggs are hatched. The nest is constructed, at the beginning of the rainy season, of leaves and is sometimes placed in a hole scooped out of the beach."
=The Sisoridæ.=—The Sisoridæ are small catfishes found in swift mountain streams of northern India. In some of the genera (Pseudecheneis) in swift streams a sucking-disk formed of longitudinal plates of skin is formed on the breast. This enables these fishes to resist the force of the water. In one genus, Exostoma, plates of skin about the mouth serve the same purpose.
The Bunocephalidæ are South American catfishes with the dorsal fin undeveloped and the top of the head rough. In Platystacus (Aspredo), the eggs are carried on the belly of the female, which is provided with spongy tentacles to which the eggs are attached. After the breeding season the ventral surface becomes again smooth.
=The Plotosidæ.=—The Plotosidæ are naked catfishes, largely marine, found along the coasts of Asia. In these fishes the second dorsal is very long. Plotosus anguillaris, the sea catfish of Japan, is a small species striped with yellow and armed with sharp pectoral spines which render it a very disagreeable object to the fishermen. In sandy bays like that of Nagasaki it is very abundant. Allied to this is the small Asiatic family of Chacidæ.
=The Chlariidæ.=—The Chlariidæ are eel-like, with a soft skeleton and a peculiar accessory gill. These abound in the swamps and muddy streams of India, where some species reach a length of six feet. One species, Chlarias magur, has been brought by the Chinese to Hawaii, where it flourishes in the same waters as Ameiurus nebulosus, brought from the Potomac and by Chinese carried from San Francisco.
=The Hypophthalmidæ and Pygidiidæ.=—The Hypophthalmidæ have the minute air-bladder inclosed in a long bony capsule. The eyes are placed very low and the skin is smooth. The statement that this family lacks the auditory apparatus is not correct. The few species belong to northern South America.
Allied to this group is the family Pygidiidæ with a differently formed bony capsule and no adipose fin. The numerous species are all South American, mostly of mountain streams of high altitude. Some are very small. Certain species are said to flee for protection into the gill-cavity of larger catfishes. Some are reported to enter the urethra of bathers, causing severe injuries. The resemblance of certain species to the loaches, or Cobitidæ, is very striking. This similarity is due to the results of similar environment and necessarily parallel habits. The Argidæ have the capsule of the air-bladder formed in a still different fashion. The few species are very small, inhabitants of the streams of the high Andes.
=The Loricariidæ.=—In the family of Loricariidæ the sides and back are armed with rough bony plates. The small air-bladder is still in a bony capsule, and the mouth is small with thick fringed lips. The numerous species are all small fishes of the South American waters, bearing a strong external resemblance to Agonidæ, but wholly different in anatomy.
=The Callichthyidæ.=—The Callichthyidæ are also small fishes armed with a bony interlocking coat of mail. They are closely allied to the Pygidiidæ. The body is more robust than in the Callichthyidæ and the coat of mail is differently formed. The species swarm in the rivers of northern South America, where with the mailed Loricariidæ they form a conspicuous part of the fish fauna.
=Fossil Catfishes.=—Fossil catfishes are very few in number. Siluridæ, allied to Chlarias, Bagarius, Heterobranchus, and other fresh-water forms of India, are found in the late Tertiary rocks of Sumatra, and catfish spines exist in the Tertiary rocks of the United States. Vertebræ in the Canadian Oligocene have been referred by Cope to species of Ameiurus (A. cancellatus and A. maconnelli). Rhineastes peltatus and six other species, perhaps allied to Pimelodus, have been described by Cope from Eocene of Wyoming and Colorado. Bucklandium diluvii is found in the Eocene London clays, and several species apparently marine, referred to the neighborhood of Tachysurus or Arius, are found in Eocene rocks of England.
There is no evidence that the group of catfishes has any great antiquity, or that its members were ever so numerous and varied as at the present time. The group is evidently derived from scaly ancestors, and its peculiarities are due to specialization of certain parts and degeneration of others.
There is not the slightest reason for regarding the catfishes as direct descendants of the sturgeon or other Ganoid type. They should rather be looked upon as a degenerate and highly modified offshoot from the primitive Characins.
=Order Gymnonoti.=—At the end of the series of Ostariophysans we may place the Gymnonoti (γυμνός, bare; νῶτος, back). This group contains about thirty species of fishes from the rivers of South America and Central America. All are eel-like in form, though the skeleton with the shoulder-girdle suspended from the cranium is quite unlike that of a true eel. There is no dorsal fin. The vent is at the throat and the anal is excessively long. The gill-opening is small as in the eel, and as in most elongate fishes, the ventral fins are undeveloped. The body is naked or covered with small scales.
Two families are recognized, differing widely in appearance. The Electrophoridæ constitutes by itself Cope's order of Glanencheli (γλανίς, catfish; ἔγχελυς, eel). This group he regards as intermediate between the eel-like catfishes (Chlarias) and the true eels. It is naked and eel-shaped, with a short head and projecting lower jaw like that of the true eel. The single species, Electrophorus electricus, inhabits the rivers of Brazil, reaching a length of six feet, and is the most powerful of all electric fishes. Its electric organs on the tail are derived from modified muscular tissue. They are described on p. 170, Vol. I.
The Gymnotidæ are much smaller in size, with compressed scaly bodies and the mouth at the end of a long snout. The numerous species are all fishes without electric organs. Eigenmannia humboldti of the Panama region is a characteristic species. No fossil Gymnonoti are recorded.
X. THE SCYPHOPHORI, HAPLOMI, AND XENOMI
=ORDER Scyphophori.=—The Scyphophori (σκύφος, cup; φορέω, to bear) constitutes a small order which lies apparently between the Gymnonoti and the Isospondyli. Boulenger unites it with the Isospondyli. The species, about seventy-five in number, inhabit the rivers of Africa, where they are important as food-fishes. In all there is a deep cavity on each side of the cranium covered by a thin bony plate, the supertemporal bone. There is no symplectic bone, and the subopercle is very small or concealed. The gill-openings are narrow and there are no pharyngeal teeth. The air-bladder connects with the ear, but not apparently in the same way as with the Ostariophysan fishes, to which, however, the Scyphophori are most nearly related. In all the Scyphophori the body is oblong, covered with cycloid scales, the head is naked, there are no barbels, and the small mouth is at the end of a long snout. All the species possess a peculiar organ on the tail, which with reference to a similar structure in Torpedo and Electrophorus is held to be a degenerate electric organ. According to Günther, "it is without electric functions, but evidently representing a transitional condition from muscular substance to an electric organ. It is an oblong capsule divided into numerous compartments by vertical transverse septa and containing a gelatinous substance."
=The Mormyridæ.=—There are two families of Scyphophori. The Mormyridæ have the ordinary fins and tail of fishes and the Gymnarchidæ are eel-like, with ventrals, anal and caudal wanting. Gymnarchus miloticus of the Nile reaches a length of six feet, and it is remarkable as retaining the cellular structure of the air-bladder as seen in the garpike and bowfin. It doubtless serves as an imperfect lung.
The best-known genus of Scyphophori is Mormyrus. Species of this genus found in the Nile were worshiped as sacred by the ancient Egyptians and pictures of Mormyrus are often seen among the emblematic inscriptions. The Egyptians did not eat the Mormyrus because with two other fishes it was accused of having devoured a limb from the body of Osiris, so that Isis was unable to recover it when she gathered the scattered remains of her husband.
In Mormyrus the bones of the head are covered by skin, the snout is more or less elongated, and the tail is generally short and insignificant. One of the most characteristically eccentric species is Gnathonemus curvirostris, lately discovered by Dr. Boulenger from the Congo. Fossil Mormyridæ are unknown.
=The Haplomi.=—In the groups called Iniomi and Lyopomi, the mesocoracoid arch is imperfect or wanting, a condition which in some cases may be due to the degeneration produced by deep-sea life. In the eels a similar condition obtains. In the group called Haplomi (ἁπλοός, simple; ὤμος, shoulder), as in all the groups of fishes yet to be discussed, this arch is wholly wanting at all stages of development. In common with the Isospondyli and with soft-rayed fishes in general the air-bladder has a persistent air-duct, all the fins are without true spines, the ventral fins are abdominal, and the scales are cycloid. The group is a transitional one, lying almost equidistant between the Isospondyli and the Acanthopterygii. Gill unites it with the latter and Woodward with the former. We may regard it for the present as a distinct order, although no character of high importance separates it from either. Hay unites the _Haplom_i with the Synentognathi to form the order of Mesichthyes, or transitional fishes, but the affinities of either with other groups are quite as well marked as their relation to each other. Boulenger unites the Iniomi with the Haplomi, an arrangement which apparently has merit, for the most primitive and non-degenerate Iniomi, as Aulopus and Synodus, lack both mesocoracoid and orbitosphenoid. These bones are characteristic of the Isospondyli, but are wanting in Haplomi.
There is no adipose dorsal in the typical Haplomi, the dorsal is inserted far back, and the head is generally scaly. Most but not all of the species are of small size, living in fresh or brackish water, and they are found in almost all warm regions, though scantily represented in California, Japan, and Polynesia. The four families of typical Haplomi differ considerably from one another and are easily distinguished, although obviously related. Several other families are provisionally added to this group on account of agreement in technical characters, but their actual relationships are uncertain.
=The Pikes.=—The Esocidæ have the body long and slender and the mouth large, its bones armed with very strong, sharp teeth of different sizes, some of them being movable. The upper jaw is not projectile, and its margin, as in the Salmonidæ, is formed by the maxillary. The scales are small, and the dorsal fin far back and opposite the anal, and the stomach is without pyloric cæca. There is but a single genus, Esox (Lucius of Rafinesque), with about five or six living species. Four of these are North American, the other one being found in Europe, Asia, and North America.
All the pikes are greedy and voracious fishes, very destructive to other species which may happen to be their neighbors; "mere machines for the assimilation of other organisms." Thoreau describes the pike as "the swiftest, wariest, and most ravenous of fishes, which Josselyn calls the river-wolf. It is a solemn, stately, ruminant fish, lurking under the shadow of a lily-pad at noon, with still, circumspect, voracious eye; motionless as a jewel set in water, or moving slowly along to take up its position; darting from time to time at such unlucky fish or frog or insect as comes within its range, and swallowing it at one gulp. Sometimes a striped snake, bound for greener meadows across the stream, ends its undulatory progress in the same receptacle."
As food-fishes, all the Esocidæ rank high. Their flesh is white, fine-grained, disposed in flakes, and of excellent flavor.
The finest of the Esocidæ, a species to be compared, as a grand game fish, with the salmon, is the muskallunge (Esox masquinongy). Technically this species may be known by the fact that its cheeks and opercles are both naked on the lower half. It may be known also by its great size and by its color, young and old being spotted with black on a golden-olive ground.
The muskallunge is found only in the Great Lake region, where it inhabits the deeper waters, except for a short time in the spring, when it enters the streams to spawn. It often reaches a length of six feet and a weight of sixty to eighty pounds. It is necessarily somewhat rare, for no small locality would furnish food for more than one such giant. It is, says Hallock, "a long, slim, strong, and swift fish, in every way formed for the life it leads, that of a dauntless marauder."
A second species of muskallunge, Esox ohiensis, unspotted but vaguely cross-barred, occurs sparingly in the Ohio River and the upper Mississippi Valley. It is especially abundant in Chautauqua Lake.
The pike (Esox lucius) is smaller than the muskallunge, and is technically best distinguished by the fact that the opercles are naked below, while the cheeks are entirely scaly. The spots and cross-bars in the pike are whitish or yellowish, and always paler than the olive-gray ground color. It is the most widely distributed of all fresh-water fishes, being found from the upper Mississippi Valley, the Great Lakes, and New England to Alaska and throughout northern Asia and Europe. It reaches a weight of ten to twenty pounds or more, being a large strong fish in its way, inferior only to the muskallunge. In England Esox lucius is known as the pike, while its young are called by the diminutive term pickerel. In America the name pickerel is usually given to the smaller species, and sometimes even to Esox lucius itself, the word being with us a synonym for pike, not a diminutive.
Of the small pike or pickerel we have three species in the eastern United States. They are greenish in color and banded or reticulated, rather than spotted, and, in all, the opercles as well as the cheeks are fully covered with scales. One of these (Esox reticulatus) is the common pickerel of the Eastern States, which reaches a respectable size and is excellent as food. The others, Esox americanus along the Atlantic seaboard and Esox vermiculatus in the middle West, seldom exceed a foot in length and are of no economic importance.
Numerous fossil species are found in the Tertiary of Europe, Esox lepidotus from the Miocene of Baden being one of the earliest and the best known; in this species the scales are much larger than in the recent species. The fossil remains would seem to indicate that the origin of the family was in southern Europe, although most of the living species are American.
=The Mud-minnows.=—Close to the pike is the family of Umbridæ, or mud-minnows, which technically differ from the pikes only in the short snout, small mouth, and weak dentition. The mud-minnows are small, sluggish, carnivorous fishes living in the mud at the bottom of cold, clear streams and ponds. They are extremely tenacious of life, though soon suffocated in warm waters. The barred mud-minnow of the prairies of the middle West (Umbra limi) often remains in dried sloughs and bog-holes, and has been sometimes plowed up alive. Umbra pygmæa, a striped species, is found in the Eastern States and Umbra crameri in bogs and brooks along the Danube. This wide break in distribution seems to indicate a former wide extension of the range of Umbridæ, perhaps coextensive with Esox. Fossil Umbridæ are, however, not yet recognized.
=The Killifishes.=—Most of the recent Haplomi belong to the family of Pœciliidæ (killifishes, or Cyprinodonts). In this group the small mouth is extremely protractile, its margin formed by the premaxillaries alone much as in the spiny-rayed fishes. The teeth are small and of various forms according to the food. In most of the herbivorous forms they are incisor-like, serrate, and loosely inserted in the lips. In the species that eat insects or worms they are more firmly fixed. The head is scaly, the stomach without cæca, and the intestines are long in the plant-eating species and short in the others. There are nearly 200 species, very abundant from New England and California southward to Argentina, and in Asia and Africa also. In regions where rice is produced, they swarm in the rice swamps and ditches. Some of them enter the sea, but none of them go far from shore. Some are brilliantly colored, and in many species the males are quite unlike the females, being smaller and more showy. The largest species (Fundulus, Anableps) rarely reach the length of a foot, while Heterandria formosa, a diminutive inhabitant of the Florida rivers, scarcely reaches an inch. Some species are oviparous, but in most of the herbivorous forms, and some of the others, the eggs are hatched within the body, and the anal in the male is modified into a long sword-shaped intromittent organ, placed farther forward than the anal in the female. The young when born closely resemble the parent. Most of the insectivorous species swim at the surface, moving slowly with the eyes partly out of water. This habit in the genus Anableps (four-eyed fish, or Cuatro ojos) is associated with an extraordinary structure of the eye. This organ is prominent and is divided by a horizontal partition into two parts, the upper, less convex, adopted for sight in the air, the lower in the water. The few species of Anableps are found in tropical America. The species of some genera swim near the bottom, but always in very shallow waters. All are very tenacious of life, and none have any commercial value although the flesh is good.
The unique structure of the eye of this curious fish has been carefully studied by Mr. M. C. Marsh, pathologist of the U. S. Fish Commission, who furnishes the following notes published by Evermann & Goldsborough:
"The eye is crossed by a bar, like the diameter of a circle, and parallel with the length of the body. This bar is darker than the other external portions of the eyeball and has its edges darker still. Dividing the external aspect of the eye equally, it has its lower edge on the same level as the back of the fish, which is flat and straight from snout to dorsal, or nearly the whole length of the fish; so that when the body of the fish is just submerged the level of the water reaches to this bar, and the lower half of the eye is in water, the upper half in the air. Upon dissecting the eyeball from the orbit, it appears nearly round. A membranous sheath covers the external part and invests most of the ball. It may be peeled off, when the dark bar on the external portion of the eye is seen to be upon this membrane, which may correspond to the conjunctiva. The back portion of the eyeball being cut off, one lens is found. The lining of the ball consists, in front, of one black layer, evidently choroid. Behind there is a retinal layer. The choroid layer turns up anteriorly, making a free edge comparable to an iris. The free edge is chiefly evident in the lower part of the eye. A large pupil is left, but is divided by two flaps, continuations of the choroid coat, projecting from either side and overlapping. There are properly then two pupils, an upper and lower, separated by a band consisting of the two flaps, which may probably, by moving upward and downward, increase or diminish the size of either pupil; an upward motion of the flaps increasing the lower pupil at the expense of the other, and vice versa."
This division of the pupil into two parts permits the fish, when swimming at the surface of the water, as is its usual custom, to see in the air with the upper portion and in the water with the lower. It is thus able to see not only such insects as are upon the surface of the water or flying in the air above, but also any that may be swimming beneath the surface.
According to Mr. E. W. Nelson, "the individuals of this species swim always at the surface and in little schools arranged in platoons or abreast. They always swim headed upstream against the current, and feed upon floating matter which the current brings them. A platoon may be seen in regular formation breasting the current, either making slight headway upstream or merely maintaining their station, and on the qui vive for any suitable food the current may bring. Now and then one may be seen to dart forward, seize a floating food particle, and then resume its place in the platoon. And thus they may be observed feeding for long periods. They are almost invariably found in running water well out in the stream, or at least where the current is strongest and where floating matter is most abundant, for it is upon floating matter that they seem chiefly to depend. They are not known to jump out of the water to catch insects flying in the air or resting upon vegetation above the water surface, nor do they seem to feed to any extent upon all small crustaceans or other portions of the plankton beneath the surface.
"When alarmed—and they are wary and very easily frightened—they escape by skipping or jumping over the water, 2 or 3 feet at a skip. They rise entirely out of the water, and at a considerable angle, the head pointing upward. In descending the tail strikes the water first and apparently by a sculling motion new impetus is acquired for another leap. This skipping may continue until the school is widely scattered. When a school has become scattered, and after the cause of their fright has disappeared, the individuals soon rejoin each other. First two will join each other and one by one the others will join them until the whole school is together again. Rarely do they attempt to dive or get beneath the surface; when they do they have great difficulty in keeping under and soon come to the surface again."
Of the many genera of Pœciliidæ, top-minnows, and killifishes we may mention the following: Cyprinodon is made up of chubby little fishes of eastern America with tricuspid, incisor teeth, oviparous and omnivorous. Very similar to these but smaller are the species of Lebias in southern Europe. Jordanella floridæ of the Florida everglades is similar, but with the dorsal fin long and its first ray enlarged and spine-like. It strongly resembles a young sunfish. Most of the larger forms belong to Fundulus, a genus widely distributed from Maine to Guatemala and north to Kansas and southern California. Fundulus majalis, the Mayfish of the Atlantic Coast, is the largest of the genus. Fundulus heteroclitus, the killifish, the most abundant. Fundulus diaphanus inhabits sea and lake indiscriminately. Fundulus stellifer of the Alabama is beautifully colored, as is Fundulus zebrinus of the Rio Grande. The genus Zygonectes includes dwarf species similar to Fundulus, and Adinia includes those with short, deep body. Goodea atripinnis with tricuspid teeth lives in warm springs in Mexico, and several species of Goodea, Gambusia, Pœcilia, and other genera inhabit hot springs of Mexico, Central America, and Africa. The genus Gambusia, the top-minnows, includes numerous species with dwarf males having the anal modified. Gambusia affinis abounds in all kinds of sluggish water in the southern lowlands, gutters and even sewers included. It brings forth its brood in early spring. Viviparous and herbivorous with modified anal fin are the species of Pœcilia, abundant throughout Mexico and southward to Brazil; Mollienesia very similar, with a banner-like dorsal fin, showily marked, occurs from Louisiana southward, and Xiphophorus, with a sword-shaped lobe on the caudal, abounds in Mexico; Characodon and Goodea (see Fig. 53, Vol. I) in Mexico have notched teeth, and finally, Heterandria contains some of the least of fishes, the handsomely colored males barely half an inch long.
In Lake Titicaca in the high Andes is a peculiar genus (Orestias) without ventral fins. Still more peculiar is Empetrichthys merriami of the desert springs of the hot and rainless Death Valley in California, similar to Orestias, but with enormously enlarged pharyngeals and pharyngeal teeth, an adaptation to some unknown purpose. Fossil Cyprinodonts are not rare from the Miocene in southern Europe. The numerous species are allied to Lebias and Cyprinodon, and are referred to Prolebias and Pachylebias. None are American, although two American extinct genera, Gephyrura and Proballostomus, are probably allied to this group.
=Amblyopsidæ.=—The cavefishes, Amblyopsidæ, are the most remarkable of the haplomous fishes. In this family the vent is placed at the throat. The form is that of the Pœciliidæ, but the mouth is larger and not protractile. The species are viviparous, the young being born at about the length of a quarter of an inch.
In the primitive genus Chologaster, the fish of the Dismal Swamp, the eyes are small but normally developed. Chologaster cornutus abounds in the black waters of the Dismal Swamp of Virginia, thence southward through swamps and rice-fields to Okefinokee Swamp in northern Florida. It is a small fish, less than two inches long, striped with black, and with the habit of a top-minnow. Other species of Chologaster, possessing eyes and color, but provided also with tactile papillæ, are found in cave springs in Tennessee and southern Illinois.
From Chologaster is directly descended the small blindfish Typhlichthys subterraneus of the caves of the Subcarboniferous limestone rocks of southern Indiana and southward to northern Alabama. As in Chologaster, the ventral fins are wanting. The eyes, present in the young, become defective and useless in the adult, when they are almost hidden by other tissues. The different parts of the eye are all more or less incomplete, being without function. The structure of the eye has been described in much detail in several papers by Dr. Carl H. Eigenmann. As to the cause of the loss of eyesight two chief theories exist—the Lamarckian theory of the inheritance in the species of the results of disuse in the individual and the Weissmannian doctrine that the loss of sight is a result of panmixia or cessation of selection. This may be extended to cover reversal of selection, as in the depths of the great caves the fish without eyes would be at some slight advantage. Dr. Eigenmann inclines to the Lamarckian doctrine, but the evidence brought forward fails to convince the present writer that results of individual use or disuse ever become hereditary or that they are ever incorporated in the characters of a species. In the caves of southern Missouri is an independent case of similar degradation. Troglichthys rosæ, the blindfish of this region, has the eye in a different phase of degeneration. It is thought to be separately descended from some other species of Chologaster. Of this species Mr. Garman and Mr. Eigenmann have given detailed accounts from somewhat different points of view.
Concerning the habits of the blindfish (Troglichthys rosæ), Mr. Garman quotes the following from notes of Miss Ruth Hoppin, of Jasper County, Missouri: "For about two weeks I have been watching a fish taken from a well. I gave him considerable water, changed once a day, and kept him in an uninhabited place subject to as few changes of temperature as possible. He seems perfectly healthy and as lively as when first taken from the well. If not capable of long fasts, he must live on small organisms my eye cannot discern. He is hardly ever still, but moves about the sides of the vessel constantly, down and up, as if needing the air. He never swims through the body of the water away from the sides unless disturbed. Passing the finger over the sides of the vessel under water I find it slippery. I am careful not to disturb this slimy coating when the water is changed.... Numerous tests convince me that it is through the sense of touch, and not through hearing, that the fish is disturbed; I may scream or strike metal bodies together over him as near as possible, yet he seems to take no notice whatever. If I strike the vessel so that the water is set in motion, he darts away from that side through the mass of water, instead of around in his usual way. If I stir the water or touch the fish, no matter how lightly, his actions are the same."
The more famous blindfish of the Mammoth Cave, Amblyopsis spelæus, reaches a length of five inches. It possesses ventral fins. From this fact we may infer its descent from some extinct genus which, unlike Chologaster, retains these fins. The translucent body, as in the other blindfishes, is covered with very delicate tactile papillæ, which form a very delicate organ of touch.
The anomalous position of the vent in Amblyopsidæ occurs again in an equally singular fish, Aphredoderus sayanus, which is found in the same waters throughout the same region in which Chologaster occurs. It would seem as if these lowland fishes of the southern swamps were remains of a once much more extensive fauna.
No fossil allies of Chologaster are known.
=Kneriidæ, etc.=—The members of the order of Haplomi, recorded above, differ widely among themselves in various details of osteology. There are other families, probably belonging here, which are still more aberrant. Among these are the Kneriidæ, and perhaps the entire series of forms called Iniomi, most of which possess the osteological traits of the Haplomi.
The family of Kneriidæ includes a few very small fishes of the rivers of Africa.
=The Galaxiidæ.=—The Galaxiidæ are trout-like fishes of the southern rivers, where they take the place of the trout of the northern zones. The species lack the adipose fins and have the dorsal inserted well backward. According to Boulenger these fishes, having no mesocoraoid, should be placed among the Haplomi. Yet their relation to the Haplochitonidæ is very close and both families may really belong to the Isospondyli. Galaxias truttaceus is the kokopu, or "trout," of New Zealand. Galaxias ocellatus is the yarra trout of Australia. Several other species are found in southern Australia, Tasmania, Patagonia, and the Falkland Islands, and even in South Africa. This very wide distribution in the rivers remote from each other has given rise to the suggestion of a former land connection between Australia and Patagonia. Other similar facts have led some geologists to believe in the existence of a former great continent called Antarctica, now submerged except that part which constitutes the present unknown land of the Antarctic.
As intimated on p. 253, Vol. I, this distribution of Galaxias with similar anomalies in other groups could not if unsupported by geological evidence be held to prove the former extension of the Antarctic continent. Dr. Boulenger[12] has recently shown that Galaxias lives freely in salt water, a fact sufficient to account for its wide distribution in the rivers of the southern hemisphere.
Footnote 12:
Dr. Boulenger (Nature, Nov. 27, 1902) has the following note on Galaxias: "Most text-books and papers discussing geographical distribution have made much of the range of a genus of small fishes, somewhat resembling trout, the Galaxias, commonly described as true fresh-water forms, which have long been known from the extreme south of South America, New Zealand, Tasmania, and southern Australia. The discovery, within the last few years, of a species of the same genus in fresh water near Cape Town, whence it had previously been described as a loach by F. de Castelnau, has added to the interest, and has been adduced as a further argument in support of the former existence of an Antarctic continent. In alluding to this discovery when discussing the distribution of African fresh-water fishes in the introduction to my work 'Les Poissons du Bassin du Congo,' in 1901, I observed that, contrary to the prevailing notion, all species of Galaxias are not confined to fresh water, and that the fact of some living both in the sea and in rivers suffices to explain the curious distribution of the genus; pointing out that in all probability these fishes were formerly more widely distributed in the seas south of the tropic of Capricorn, and that certain species, adapting themselves entirely to fresh-water life, have become localized at the distant points where they are now known to exist. Although as recently as October last the distinguished American ichthyologist D. S. Jordan wrote (Science, xiv, p. 20): 'We know nothing of the power of Galaxias to survive submergence in salt water, if carried in a marine current': it is an established fact, ascertained some years ago by F. E. Clarke in New Zealand and by R. Vallentin in the Falkland Islands, that Galaxias attenuatus lives also in the sea. In New Zealand it periodically descends to the sea, where it spawns, from January to March, and returns from March to May. In accordance with these marine habits, this species has a much wider range than any of the others, being known from Chile, Patagonia, Tierra del Fuego, the Falkland Islands, New Zealand, Tasmania, and southern Australia.
"I now wish to draw attention to a communication made by Captain F. W. Hutton in the last number of the Transactions of the New Zealand Institute (xxxiv, p. 198), 'On a Marine Galaxias from the Auckland Islands.' This fish, named Galaxias bollansi, was taken out of the mouth of a specimen of Merganser australis during the collection excursion to the southern islands of New Zealand made in January, 1901, by His Excellency the Earl of Ranfurly.
"It is hoped that by giving greater publicity to these discoveries the family Galaxiidæ will no longer be included among those strictly confined to fresh waters, and that students of the geographical distribution of animals will be furnished with a clue to a problem that has so often been discussed on insufficient data. As observed by Jordan (l. c.), all anomalies in distribution cease to be such when the facts necessary to understand them are at hand.'
"Of the fresh-water species of Galaxias, eight are known from New Zealand and the neighboring islands, seven from New South Wales, three or four from south Australia, one from west Australia, two from Tasmania, seven from South America, from Chile southwards, and one from the Cape of Good Hope."
Neochanna is an ally of Galaxias living in burrows in the clay or mud like a crayfish, often at a distance from water. As in various other mud-living types, the ventral fins are obsolete.
=Order Xenomi.=—We must place near the Haplomi the singular group of Xenomi (ξενός, strange; ὤμος, shoulder), regarded by Dr. Gill as a distinct order. Externally these fish much resemble the mud-minnows, differing mainly in the very broad pectorals. But the skeleton is thin and papery, the two coracoids forming a single cartilaginous plate imperfectly divided. The pectorals are attached directly to this without the intervention of actinosts, but in the distal third, according to Dr. Charles H. Gilbert, the coracoid plate begins to break up into a fringe of narrow cartilaginous strips. These about equal the very large number (33 to 36) of pectoral rays, the basal part of each ray being slightly forked to receive the tip of the cartilaginous strip.
"In the deep-sea eels of the order Heteromi there is a somewhat similar condition of the coracoid elements inasmuch as the hypercoracoid and hypocoracoid though present are merely membranous elements surrounded by cartilage and the actinosts are greatly reduced. It seems probable that we are dealing in the two cases with independent degeneration of the shoulder-girdle and that the two groups (Xenomi and Heteromi) are not really related." (Gilbert.)
Of the single family Dalliidæ, one species is known, the Alaska blackfish, Dallia pectoralis.
This animal, formed like a mud-minnow, reaches a length of eight inches and swarms in the bogs and sphagnum swamps of northwestern Alaska and westward through Siberia. It is found in countless numbers according to its discoverer, Mr. L. M. Turner, "wherever there is water enough to wet the skin of a fish," and wherever it occurs it forms the chief food of the natives. Its vitality is most extraordinary. Blackfishes will remain frozen in baskets for weeks and when thawed out are as lively as ever. Turner gives an account of a frozen individual swallowed by a dog which escaped in safety after being thawed out by the heat of the dog's stomach.
XI. ACANTHOPTERYGII; SYNENTOGNATHI
=ORDER Acanthopterygii, the Spiny-rayed Fishes.=—The most of the remaining bony fishes constitute a natural group for which the name Acanthopterygii (ἄκανθα, spine; πτερύξ, πτερόν, fin or wing) may be used. This name is often written Actinopteri, a form equally correct and more euphonious and convenient. These fishes are characterized, with numerous exceptions, by the presence of fin spines, by the connection of the ventral fins with the shoulder-girdle, by the presence in general of more than one spine in the anterior part of dorsal and anal fins, and as a rule of one spine and five rays in the ventral fins, and by the absence in the adult of a duct to the air-bladder. Minor characters are these: the pectoral fins are inserted high on the shoulder-girdle, the scales are often ctenoid, and the edge of the upper jaw is formed by the premaxillary alone, the maxillary being always toothless.
But it is impossible to define or limit the group by any single character or group of characters. It is connected with the Malacopterygii through the Haplomi on the one hand by transitional groups of genera which may lack any one of these characters. On the other hand, in the extreme forms, each of these distinctive characters may be lost through degeneration. Thus fin spines, ctenoid scales, and the homocercal tail are lost in the codfishes, the connection of ventrals with shoulder-girdle fails in the Percesoces, etc., and the development of the air-duct is subject to all sorts of variations. In one family even the adipose fin remains through all the changes and modifications the species have undergone.
The various transitional forms between the Haplomi and the perch-like fishes have been from time to time regarded as separate orders. Some of them are more related to the perch, others rather to ancestors of salmon or pike, while still others are degenerate offshoots, far enough from either.
On the whole, all these forms, medium, extreme and transitional, may well be placed in one order, which would include the primitive flying-fishes and mullets, the degraded globefishes, and the specialized flounders. As for the most part these are spiny-rayed fishes, Cuvier's name Acanthopterygii, or Acanthopteri, will serve us as well as any. The Physoclysti of Müller, the Thoracices of older authors, and the Ctenoidei of Agassiz include substantially the same series of forms. The order Teleocephali of Gill (τελεός, perfect; κεφαλή, head) has been lately so restricted as to cover nearly the same ground. In Gill's most recent catalogue of families, the order Teleocephali includes the Haplomi and rejects the Hemibranchii, Lophobranchii, Plectognathi, and Pediculati, all of these being groups characterized by sharply defined but comparatively recent characters not of the highest importance. As originally arranged, the order Teleocephali included the soft-rayed fishes as well. From it the Ostariophysi were first detached, and still later the Isospondyli were regarded by Dr. Gill as a separate order.
We may first take up serially as suborders the principal groups which serve to effect the transition from soft-rayed to spiny-rayed fishes.
=Suborder Synentognathi.=—Among the transitional forms between the soft-rayed and the spiny-rayed fishes, one of the most important groups is that known as Synentognathi (σύν, together; ἔν, within; γνάθος, jaw). These have, in brief, the fins and shoulder-girdle of Haplomi, the ventral fins abdominal, the dorsal and anal without spines. At the same time, as in the spiny-rayed fishes, the air-bladder is without duct and the pectoral fins are inserted high on the side of the body. With these traits are two others which characterize the group as a suborder. The lower pharyngeal bones are solidly united into one bone and the lateral line forms a raised ridge along the lower side of the body. These forms are structurally allied to the pikes (Haplomi), on the one hand, and to the mullets (Percesoces), on the other, and this relationship accords with their general appearance. In this group as in all the remaining families of fishes, there is no mesocoracoid, and in very nearly all of these families the duct to the air-bladder disappears at an early stage of development.
=The Garfishes: Belonidæ.=—There are two principal groups or families among the Synentognathi, the Belonidæ, with strong jaws and teeth, and the Exocœtidæ, in which these structures are feeble. Much more important characters appear in the anatomy. In the Belonidæ the third upper pharyngeal is small, with few teeth, and the maxillary is firmly soldered to the premaxillary. The vertebræ are provided with zygapophyses. The species of Belonidæ are known as garfishes, or needle-fishes. They resemble the garpike in form, but have nothing else in common. The body is long and slender, covered with small scales. Sharp, unequal teeth fill the long jaws and the dorsal is opposite the anal, on the hinder part of the body. These fishes are green in color, even the bones being often bright green, while the scales on the sides have a silvery luster. The species are excellent as food, the green color being associated with nothing deleterious. All are very voracious and some of the larger species, 5 or 6 feet long, may be dangerous even to man. Fishermen have been wounded or killed by the thrust of the sharp snout of a fish springing into the air. The garfishes swim near the surface of the water and often move with great swiftness, frequently leaping from the water. The genus Belone is characterized by the presence of gill-rakers. Belone belone is a small garfish common in southern Europe. Belone platura occurs in Polynesia. The American species (Tylosurus) lack gill-rakers. Tylosurus marinus, the common garfish of the eastern United States, often ascends the rivers. Tylosurus raphidoma, Tylosurus fodiator, Tylosurus acus, and other species are very robust, with short strong jaws. Athlennes hians is a very large fish with the body strongly compressed, almost ribbon-like. It is found in the West Indies and across the Isthmus as far as Hawaii. Many other species, mostly belonging to Tylosurus, abound in the warm seas of all regions. Tylosurus ferox is the long tom of the Australian markets. Potamorrhaphis with the dorsal fin low is found in Brazilian rivers. A few fossil species are referred to Belone, Belone flava from the lower Eocene being the earliest.
=The Flying-fishes: Exocœtidæ.=—The family of Exocœtidæ includes the flying-fishes and several related forms more or less intermediate between these and the garfishes. In these fishes the teeth are small and nearly equal and the maxillary is separate from the premaxillary. The third upper pharyngeal is much enlarged and there are no zygapophyses to the vertebræ.
The skippers (Scombresox) have slender bodies, pointed jaws, and, like the mackerel, a number of detached finlets behind dorsal and anal, although in other respects they show no affinity to the mackerel. The common skipper, or saury (Scombresox saurus), is found on both shores of the North Atlantic swimming in large schools at the surface of the water, frequently leaping for a little distance like the flying-fish. They are pursued by the mackerel-like fishes, as the tunny or bonito, and sometimes by porpoises. According to Mr. Couch, the skippers, when pursued, "mount to the surface in multitudes and crowd on each other as they press forward. When still more closely pursued, they spring to the height of several feet, leap over each other in singular confusion, and again sink beneath. Still further urged, they mount again and rush along the surface, by repeated starts, for more than one hundred feet, without once dipping beneath or scarcely seeming to touch the water. At last the pursuer springs after them, usually across their course, and again they all disappear together. Amidst such multitudes—for more than twenty thousand have been judged to be out of the water together—some must fall a prey to the enemy; but so many hunting in company, it must be long before the pursuers abandon. From inspection we could scarcely judge the fish to be capable of such flights, for the fins, though numerous, are small, and the pectoral far from large, though the angle of their articulation is well adapted to raise the fish by the direction of their motions to the surface."
A similar species, Cololabis saira, with the snout very much shorter than in the Atlantic skipper, is the Samma of the fishermen of Japan.
The hard-head (Chriodorus atherinoides) has no beak at all and its tricuspid incisor teeth are fitted to feed on plants. In this genus, as in the flying-fishes, there are no finlets. The hard-head is an excellent food-fish abundant about the Florida Keys but not yet seen elsewhere.
Another group between the gars and the flying-fishes is that of the halfbeaks, or balaos, Hemirhamphus, etc. These are also vegetable feeders, but with much smaller teeth, and the lower jaw with a spear-like prolongation to which a bright-red membrane is usually attached. Of the halfbeaks there are several genera, all of the species swimming near the surface in schools and sometimes very swiftly. Some of them leap into the air and sail for a short distance like flying-fishes, with which group the halfbeaks are connected by easy gradations. The commonest species along our Atlantic coast is Hyporhamphus unifasciatus; a larger species, Hemirhamphus brasiliensis, abounds about the Florida Keys. Euleptorhamphus longirostris, a ribbon-shaped elongate fish, with long jaw and long pectorals, is taken in the open sea, both in the Atlantic and Pacific, being common in Hawaii. The Asiatic genus Zenarchopterus is viviparous, having the anal fin much modified in the male, forming an intromittent organ, as in the Pœciliidæ. One species occurs in the river mouths in Samoa.
The flying-fishes have both jaws short, and at least the pectoral fins much enlarged, so that the fish may sail in the air for a longer or shorter distance.
The smaller species have usually shorter fins and approach more nearly to the halfbeaks. Fodiator acutus, with sharp jaws, and Hemiexocœtus, with a short beak on the lower jaw, are especially intermediate. The flight of the flying-fishes is described in detail on p. 157, Vol. I.
The Catalina flying-fish, Cypselurus californicus, of the shore of southern California is perhaps the largest of the known species, reaching a length of 18 inches. To this genus, Cypselurus, having a long dorsal and short anal, and with ventrals enlarged as well as pectorals, belong all the species strongest in flight, Cypselurus heterurus and furcatus of the Atlantic, Cypselurus simus of Hawaii and Cypselurus agoo in Japan. The very young of most of these species have a long barbel at the chin which is lost with age.
In the genus Exonautes the base of anal fin is long, as long as that of the dorsal. The species of this group, also strong in flight, are widely distributed. Most of the European flying-fishes, as Exonautes rondeleti, Exonautes speculiger, and Exonautes vinciguerræ, belong to this group, while those of Cypselurus mostly inhabit the Pacific. The large Australian species Exonautes unicolor, Fig. 226, Vol. I, belongs to this group. In the restricted genus Exocœtus the ventral fins are short and not used in flight. Exocœtus volitans (evolans) is a small flying-fish, with short ventral fins not used for flight. It is perhaps the most widely distributed of all, ranging through almost all warm seas. Parexocœtus brachypterus, still smaller, and with shorter, grasshopper-like wings, is also very widely distributed. An excellent account of the flying-fishes of the world has been given by Dr. C. F. Lütken (1876), the University of Copenhagen, which institution has received a remarkably fine series from trading-ships returning to that port. Later accounts have been given by Jordan and Meek, and by Jordan and Evermann.
Very few fossil Exocœtidæ are found. Species of Scombresox and Hemirhamphus are found in the Tertiary, the earliest being Hemirhamphus edwardsi from the Eocene of Monte Bolca. No fossil flying-fishes are known, and the genera, Exocœtus, Exonautes, and Cypselurus are doubtless all of very recent origin.
XII. PERCESOCES AND RHEGNOPTERI
=SUBORDER Percesoces.=—In the line of direct ascending transition from the Haplomi and Synentognathi, the pike and flying-fish, towards the typical perch-like forms, we find a number of families, perch-like in essential regards but having the ventral fins abdominal.
These types, represented by the mullet, the silverside, and the barracuda, have been segregated by Cope as an order called Percesoces (Perca, perch; Esox, pike), a name which correctly describes their real affinities. In these typical forms, mullet, silverside, and barracuda, the affinities are plain, but in other transitional forms, as the threadfin and the stickleback, the relationships are less clear. Cope adds to the series of Percesoces the Ophiocephalidæ, which Gill leaves with the Anabantidæ among the spiny-rayed forms. Boulenger adds also the sand-lances (Ammodytidæ) and the threadfins (Polynemidæ), while Woodward places here the Crossognathidæ. In the present work we define the Percesoces so as to include all spiny-rayed fishes in which the ventral fins are naturally abdominal, excepting those having a reduced number of gill-bones, or of actinosts, or other peculiarities of the shoulder-girdle. The Ammodytidæ have no real affinities with the Percesoces. The Crossognathidæ and other families with abdominal ventrals and the dorsal spines wholly obsolete may belong with the Haplomi. Boulenger places the Chiasmodontidæ, the Stromateidæ, and the Tetragonuridæ among the Percesoces, an arrangement of very doubtful validity. In most of the Percesoces the scales are cycloid, the spinous dorsal forms a short separate fin, and in all the air-duct is wanting.
=The Silversides: Atherinidæ.=—The most primitive of living Percesoces constitute the large family of silversides (Atherinidæ), known as "fishes of the King," Pescados del Rey, Pesce Rey, or Peixe Re, wherever the Spanish or Portuguese languages are spoken. The species are, in general, small and slender fishes of dry and delicate flesh, feeding on small animals. The mouth is small, with feeble teeth. There is no lateral line, the color is translucent green, with usually a broad lateral band of silver. Sometimes this is wanting, and sometimes it is replaced by burnished black. Some of the species live in lakes or rivers, others in bays or arms of the sea, but never at a distance from the shore or in water of more than a few feet in depth. The larger species are much valued as food, the smaller ones, equally delicate, are fried in numbers as "whitebait," but the bones are firmer and more troublesome than in the smelts and young herring. The species of the genus Atherina, known as "friars," or "brit," are chiefly European, although some occur in almost all warm or temperate seas. These are small fishes, with the mouth relatively large and oblique and the scales rather large and firm. Atherina hepsetus and A. presbyter are common in Europe, Atherina stipes in the West Indies, Atherina bleekeri in Japan, and Atherina insularum and A. lacunosa in Polynesia. The genus Chirostoma contains larger species, with projecting lower jaw, abounding in the lakes of Mexico. Chirostoma humboldtianum is very abundant about Mexico City. Like all the other species of this genus it is remarkably excellent as food, the different species constituting the famous "Pescados Blancos" of the great lakes of Chapala and Patzcuaro of the western slope of Mexico. A very unusual circumstance is this: that numerous very closely related species occupy the same waters and are taken in the same nets. In zoology, generally, it is an almost universal rule that very closely related species occupy different geographical areas, their separation being due to barriers which prevent interbreeding. But in the lake of Chapala, near Guadalajara, Prof. John O. Snyder and the present writer, and subsequently Dr. S. E. Meek, found ten distinct species of Chirostoma, all living together, taken in the same nets and scarcely distinguishable except on careful examination. Most of these species are very abundant throughout the lake, and all reach a length of twelve to fifteen inches. These species are Chirostoma estor, Ch. lucius, Ch. sphyræna, Ch. ocotlane, Ch. lermæ, Ch. chapalæ, Ch. grandocule, Ch. labarcæ, Ch. promelas, and Ch. bartoni. A similar assemblage of species nearly all different from these was obtained by Dr. Seth E. Meek in the lake of Patzcuaro, farther south. In this lake were found Ch. attenuatum, Ch. patzcuaro, Ch. humboldtianum, Ch. grandocule, and Ch. estor. The lake of Zirahuen, near Chapala, contains Ch. estor and Ch. zirahuen.
Still another species, Ch. jordani, is found about the city of Mexico, where it is sold baked in corn-husks. Along the coasts of Peru, Chile, and Argentina is found still another assemblage of fishes of the king, with very small scales, constituting the genera Basilichthys and Gastropterus (Pisciregia). Basilichthys microlepidotus is the common Pesca del Rey of Chile. The small silversides, or "brit," of our Atlantic coast belong to numerous species of Menidia, Menidia notata to the northward and Menidia menidia to the southward being most abundant. Kirtlandia laciniata, with ragged scales, is common along the Virginia coast, and K. vagrans farther south. Another small species, very slender and very graceful, is the brook silverside Labidesthes sicculus, which swarms in clear streams from Lake Ontario to Texas. This species, three to four inches long, has the snout produced and a very bright silvery stripe along the side. Large and small species of silversides occur in the sea along the California coast, where they are known familiarly as "blue smelt" or "Peixe Re." The most important of these and the largest member of the family, reaching a length of eighteen inches, is Atherinopsis californiensis, an important food-fish throughout California, everywhere wrongly known as smelt. Atherinops affinis is much like it, but has Y-shaped teeth. Iso flos-maris, called Nami-no-hana, or flower of the surf, is a shining little fish with belly shape like that of a herring. It lives in the surf on the coast of Japan. Melanotænia nigrans of Australia (family Melanotæniidæ) has the lateral band jet-black, as has also Melaniris balsanus of the rivers of southern Mexico. Atherinosoma vorax of Australia has strong teeth like those of a barracuda.
Fossil species of Atherina occur in the Italian Eocene, the best known being Atherina macrocephala. Another species, Rhamphognathus paralepoides, allied to Menidia, occurs in the Eocene of Monte Bolca.
=The Mullets: Mugilidæ.=—The mullets (Mugilidæ) are more clumsy in form than the silversides, robust, with broad heads and stouter fin-spines. The ventral fins are abdominal but well forward, the pelvis barely touching the clavicle, a condition to be defined as "subabdominal." The small mouth is armed with very feeble teeth, often reduced to mere fringes. The stomach is muscular like the gizzard of a fowl and the species feed largely on the vegetation contained in mud. There are numerous species, mostly living in shallow bays and estuaries, but some of them are confined to fresh waters. All are valued as food and some of them under favorable conditions are especially excellent.
Most of the species belong to the genera Mugil, the mullet of all English-speaking people, although not at all related to the red mullet or surmullet of the ancient Romans, Mullus barbatus.
The mullets are stoutish fish from one to two feet long, with blunt heads, small mouths almost toothless, large scales, and a general bluish-silvery color often varied by faint blue stripes. The most important species is Mugil cephalus, the common striped mullet. This is found throughout southern Europe and from Cape Cod to Brazil, from Monterey, California, to Chile, and across the Pacific to Hawaii, Japan, and the Red Sea. Among specimens from all these regions we can detect no difference.
Professor Goode gives the following account of its habits:
"The large mullets begin to assemble along the Florida coast in schools in the height of summer, probably preparatory to spawning, and at this time the eggs commence to mature. In this season they swim at the surface, and are then pursued by enemies in the water and the air, and also fall an easy prey to the fishermen. They appear to prefer to swim against the wind, and school best with a northeast wind. They also run against the tide. In Florida the spawning season seems to extend from the middle of November to the middle of January. Some of the fishermen say that they go on the mud-flats and oyster-beds at the mouth of the river to deposit their eggs. What becomes of them after this no one seems to know, but it is probable that they spread themselves over the whole surface of water-covered country in such a manner as not to be perceptible to the fisherman, who makes no effort at this time to secure the spent, lean fish. Many of them probably find their way to the lakes and others remain wherever they find good feeding-ground, gathering flesh and recruiting strength for the great strain of the next spawning season."
Professor Goode informs us that the fishermen recognize "three distinct periods of schooling and separate runs of mullet. To what extent these are founded on tradition, or upon the necessity of change in the size of the mesh of their nets, it is impossible to say. The 'June mullet' average about five to the pound; the 'fat mullet,' which are taken from August 20 to October 1, weigh about two pounds; these have, the fishermen say, a 'roe of fat' on each side as thick as a man's thumb. The 'roe mullet' weigh about two and a half pounds and are caught in November and until Christmas. Between the seasons of 'fat mullet' and 'roe mullet' there is an intermission of two or three weeks in the fishing." Professor Goode hazards the suggestion that "the 'fat mullet' of September are the breeding fish of November, with roes in an immature state, the ova not having become fully differentiated."
The mullet feed on the bottom in quiet water, swimming head downward. The food is sifted over in the mouth, the mud rejected, and the plants, chiefly microscopic, retained. Mr. Silas Stearns compares a school of mullets to barnyard fowls feeding together. When a fish finds a rich spot the others flock about it as chickens do. The pharyngeals form a sort of filter, stopping the sand and mud, the coarse parts being ejected through the mouth. Dr. Günther thus describes this apparatus:
"The upper pharyngeals have a rather irregular form: they are slightly arched, the convexity being directed toward the pharyngeal cavity, tapering anteriorly and broad posteriorly. They are coated with a thick, soft membrane, which reaches far beyond the margin of the bone and is studded all over with minute horny cilia. Each branchial arch is provided with a series of long gill-rakers, which are laterally bent downward, each series closely fitting to the sides of the adjoining arch; they constitute together a sieve admirably adapted to permit a transit for the water, retaining at the same time every solid substance in the cavity of the pharynx."
The young mullet feed in schools and often swim with the head at the surface of the water.
We are not able to distinguish from the common striped mullet of Europe and America the mullet of Hawaii, the famous Ama-ama, the most valued of Hawaiian fishes. This species is reared in mullet ponds, made by extending a stone wall across an arm of the sea. Through openings in the wall the young mullet enter, and in its protection they grow very fat on the abundant algæ and other vegetation. They thus become the most plentiful and most esteemed of the market fishes of Honolulu. The Awa (Chanos) and the Awa-awa (Elops) also enter these ponds and are reared with the mullet, being similarly but less valued. Unfortunately the kaku, or small barracuda (Sphyræna helleri), also enters with these helpless fishes and destroys many of the smaller individuals. Another striped species, also very similar to Mugil cephalus in appearance and value, in fact indistinguishable from the Hawaiian mullet, abounds in Japan and India.
The white or unstriped mullets are generally smaller, but otherwise differ little. Mugil curema is the white mullet of tropical America, ranging occasionally northward, and several other species occur in the West Indies and the Mediterranean. The genus Mugil has the eye covered by thick transparent tissue called the adipose eyelid. In Liza the adipose eyelid is wanting. Liza capito, the big-headed mullet of the Mediterranean, is a well-known species. Most of the mullets of the south seas belong to the genus Liza. Liza melinoptera and Liza cæruleomaculata are common in Samoa. The genus Querimana includes dwarf-mullets, two or three inches long, known as whirligig-mullets. These little fishes gather in small schools and swim round and round on the surface like the whirligig-beetles, or Gyrinidæ, their habits being like those of the young mullets; some young mullets having been, in fact, described as species of Querimana. The genus Agonostomus includes fresh-water mullets of the mountain rivers of the East and West Indies and Mexico, locally known as trucha, or trout. Agonostomus nasutus of Mexico is the best-known species.
The Joturo, or Bobo, Joturus pichardi, is a very large robust and vigorous mullet which abounds at the foot of waterfalls in the mountain torrents of Cuba, eastern Mexico, and Central America. It is a good food-fish, frequently taken about Jalapa, Havana, and on the Isthmus of Panama. Its lips are very thick and its teeth are broad, serrated, loosely inserted incisors.
Fossil mullets are few. Mugil radobojanus is the earliest from the Miocene of Croatia.
=The Barracudas: Sphyrænidæ.=—The Sphyrænidæ, or barracudas, differ from the mullets in the presence of very strong teeth in the bones of the large mouth. The lateral line is also developed, there is no gizzard, and there are numerous minor modifications connected with the food and habits. The species are long, slender swift fishes, powerful in swimming and voracious to the last degree. Some of the species reach a length of six feet or more, and these are almost as dangerous to bathers as sharks would be. The long, knife-like teeth render them very destructive to nets. The numerous species are placed in the single genus Sphyræna, and some of them are found in all warm seas, where they feed freely on all smaller fishes, their habits in the sea being much like those of the pike in the lakes. The flesh is firm, delicate, and excellent in flavor. In the larger species, especially in the West Indies, it may be difficult of digestion and sometimes causes serious illness, or "ichthyosism."
Sphyræna sphyræna is the spet, or sennet, a rather small barracuda common in southern Europe. Sphyræna borealis of our eastern coast is a similar but still feebler species rarely exceeding a foot in length. These and other small species are feeble folk as compared with the great barracuda (Sphyræna barracuda) of the West Indies, a robust savage fish, also known as picuda or becuna. Sphyræna commersoni of Polynesia is a similar large species, while numerous lesser ones occur through the tropical seas. On the California coast Sphyræna argentea is an excellent food-fish, slenderer than the great barracuda but reaching a length of five feet.
Several species of fossil barracuda occur in the Italian Eocene, Sphyræna bolcensis being the earliest.
=Stephanoberycidæ.=—We may append to the Percesoces, for want of a better place, a small family of the deep sea, its affinities at present unknown. The Stephanoberycidæ have the ventrals I, 5, subabdominal, a single dorsal without spine, and the scales cycloid, scarcely imbricated, each with one or two central spines. The mouth is large, with small teeth, the skull cavernous, as in the berycoids, from which group the normally formed ventrals abdominal in position would seem to exclude it. Stephanoberyx monæ and S. gilli are found at the depth of a mile and a half below the Gulf Stream. Boulenger first placed them with the Percesoces, but more recently suggests their relationship with the Haplomi. Perhaps, as supposed by Gill, they may prove to be degenerate berycoids in which the ventral fins have lost their normal connection.
=Crossognathidæ.=—A peculiar primitive group referred by Woodward to the Percesoces is the family of Crossognathidæ of the Cretaceous period. As in these fishes there are no fin-spines, they may be perhaps better placed with the Haplomi. The dorsal fin is long, without distinct spines, and the abdominal ventrals have six to eight rays. The mouth is small, with feeble teeth, and the body is elongate and compressed. Crossognathus sabandianum occurs in the Cretaceous of Switzerland and Germany, Syllæmus latifrons and other species in the Colorado Cretaceous, and Syllæmus anglicus in England. The Crossognathidæ have probably the lower pharyngeals separate, else they would be placed among the Synentognathi, a group attached by Woodward, not without reason, to the Percesoces.
=Cobitopsidæ.=—Near the Crossognathidæ may be placed the extinct Cobitopsidæ, Cobitopsis acuta being recorded from the Oligocene of Puy-de-Dôme in France. In this species there is a short dorsal fin of about seventeen rays, no teeth, and the well-developed ventral fins are not far in front of the anal. This little fish bears a strong resemblance to Ammodytes, but the affinities of the latter genus are certainly with the ophidioid fishes, while the real relationship of Cobitopsis is uncertain.
=Suborder Rhegnopteri.=—The threadfins (Polynemidæ) are allied to the mullets, but differ from them and from all other fishes in the structure of the pectoral fin and its basal bones, or actinosts.
The pectoral fin is divided into two parts, the lower composed of free or separate rays very slender and thread-like, sometimes longer than the body. Two of the actinosts of the pectoral support the fin, one is slender and has no rays, while the fourth is plate-like and attached to the coracoids, supporting the pectoral filaments. The body is rather robust, covered with large scales, formed much as in the mullet. The lateral line extends on the caudal fin as in the Sciænidæ which group these fishes resemble in many ways. The mouth is large, inferior, with small teeth. The species are carnivorous fishes of excellent flesh, abounding on sandy shores in the warm seas. They are not very active and not at all voracious. The coloration is bluish and silvery, sometimes striped with black. Most of the species belong to the genus Polydactylus. Polydactylus virginicus, the barbudo, with seven filaments, is common in the West Indies and Florida. Polydactylus octonemus with eight filaments is more rare, but ranges further north. Polydactylus approximans, the raton of western Mexico, with six filaments, reaches San Diego. Polydactylus plebejus is common in Japan and other species range through Polynesia. In India isinglass is made from the large air-bladder of species of Polydactylus. The rare Polynemus quinquarius of the West Indies have five pectoral filaments, these being greatly elongate, much longer than the body.
No extinct Polynemidæ are recorded.