SALMONIDE, a very large and important family of malacopterous fishes, of the sub order abdominales (having the ventral fins on the abdomen and behind the pectorals), nearly allied to clupeidie (the herring kindly), but at once distinguished by the second dorsal fin. which they all have, and which is merely a fold of the skin, inclosing fat, whence it is called the adipose fin, and destitute of rays. They were all included by Linnmus in the genus saline., although now divided not only into numerous genera, but by many naturalists into several families, of whlzh one retains the name of salmonidT, and the other principal ones are eharacinidce and seopelithr. The salmonidn are generally very muscular, and possess great strength, swimming with great rapidity, even against strong currents, and some of them are capable of leaping up falls of considerable height, when there is sufficient depth of water beneath. Some of them are sea-fishes, never entering rivers, although, like the herring, pilchard, etc., they approach the shore to spawn; others are generally inhabitants of the sea, but ascend rivers to spawn, and some of them also on other occasions not yet well understood; others, again, are con stant inhabitants of fresh-water lakes, or of rivers and streams. Most of them are esteemed for the table, and some are among the most esteemed of fishes.
The restricted salmonidie of those naturalists who divide the family,"are all scaly fishes, but with the head destitute of scales and the cheeks fleshy; the upper part of the mouth is formed by the premaxillary and maxillary bones together; the hranchiostegai rays are numerous; the air-bladder is large and simple; the teeth are usually small, some times very numerous, the tongue being furnished with them, as well as the other parts of the mouth, although others have the teeth few and small, or even wanting. They are generally voracious fishes, feeding chiefly on other fishes, crustaceans, worms, etc. The salmon, salmon trout, bull trout or gray trout, trout, charr, grayling, and smelt are familiar British examples. The white fish of North America is one of the most impor tant species, and to the same genus (coregonus) belong many others, inhabiting the lakes antk rivers of the northern parts of the world, some of them, from their herring-like appearance, known as herring-salnwn and fresh-water herring. The eapelin (q.v.) is a sea-fish, never entering fresh waters. The restricted or true salmonidm are found only in the northern parts of the world, and chiefly in the colder regions.
The characinides also have the body scaly and the head destitute of scales; the upper part of the mouth is formed by the pre.maxillaries and maxillaries together; there are
only four or five branchiostegal rays; the air-bladder is divided by a constriction in the middle; the teeth are very various, wholly wanting in a few, numerous in most of the genera, present on the tongue in some, and not in others; small and feeble in some, m others large and strong; in many conical and sharp, in some flat. Most of the species feed on animal food, but a few on vegetable food alone; while so ne are omniv orous, eating with equal-readiness worms or other soft animals and fruits which fall into the water. One of those feeding exclusively on vegetable substances is the pact (myletes pats), a fish scarcely excelled by any as an article of food, which has teeth very like the molar teeth of sheep, and employs them in browsing on the plants that grow on rocks covered near the cataracts of the rivers of Guiana, and in some of the trib utaries of the Amazon. In form, it is very unlike the trout or salmon, being short, thick, and clumsy. This, however, is not unfrequent in the characinithe, which exhibit much greater variety of form. than the salmonidaa proper. Thus, in some of the genus so-rasa/nip (see PIRAYA), of which there are many species, voracious carnivorous fishes with sharp trenchant teeth, the depth of the body is almost as great as its length. The species of serrasalmo are sometimes called saw-bellied salmon, from their keeled and serrated belly. The characinidcs are all inhabitants of fresh water; some of theta African, but the greater number South American. Their flesh is, generally much esteemed.
The scopelidee differ from both the previous sections of salmonidoe in the structure of the mouth, which is formed entirely of the premaxillary hone, the maxillary lying behind. Few of them have an air-bladder Some are sea ly and some destitute of scales. The form of the body is salmon-like in some, but deep and compressed in others. They are generally marine, as the argentine (q.v.), the only British species. They abound chiefly in the warmer seas; the Mediterranean produces,some; but the greater number belong to the Chinese and East Indian seas. Some are in high repute for their fine flavor.
Australia produces none of the salmoniche. The rivers and streams of that region, however, as well as those of New Zealand, Patagonia, and the Falkland islands, produce a number of species of galarias, a genus of very trout-like form, but with no scales and no adipose fin. They are called trouts by the colonists in Australia and New Zealand, but are of very inferior quality for the table.