general, rapidly perishing when withdrawn from their native element, they are much less frequently the objects of our observation than those animals which, as sharing with us the vital13 influence of the atmosphere, and being inhabitants of the soil on which we ourselves rest, we meet with at every turn, and with the forms and habits of which we become, almost unconsciously, more or less familiar. 4. Fishes are rarely domesticated11 in our houses; we do not meet with them in our walks; they are never presented to us in our menageries; nay, we seldom find preparations of them even in our museums: we see them, for the most part, only in our markets or on our tables, and know them chiefly but as administering to our palates. If we follow them to their native haunts, 15 it is too frequently in the same spirit that we pursue the fluttering bird with our gun, or the panting hare with our hounds-in pursuit of a barbarous sport, and with no other end in view than the gratification of vanity in the contemplation of our dexterity in hooking and torturing them. 5. But are fishes, constituting, as they do, the principal inhabitants of by far the largest portion of our globe, worthy of no greater attention than this? Is their structure less wonderful, or are their habits less interesting, than those of the animals with which we are for the most part better acquainted? On the contrary, is it not reasonable to suppose that the investigation of the structure, and functions, and habits of animals so peculiarly circumstanced, will open to us sources of admiration and delight as extensive as they are novel; and, by furnishing us with so many new associations, render us still better informed with respect to animals concerning which we may flatter ourselves we have little or nothing to learn'? 6. Fishes may justly be considered to hold an important place in the mighty scale of creation, as furnishing food for man; and, viewed in this light alone, the subject is one of great importance, from the economical and commercial relations which grow out of it. We venture, moreover, to assure the student that, however devoid of interest this department of Natural History may seem to be when viewed from a distance, it offers to him a far greater variety of diversified forms of life than birds and quadrupeds united; and we also assure him that he will not fail to find, throughout its wide domains, numerous illustrations of the wisdom, goodness, and power of the Creator. Nature is ever eloquent: "Heaven, earth, and sea 1 Zo-ŎL'-O-GY, see Third Reader, p. 240. 3 PROG'-E-NY, inhabitants; descendants. 5 TELL, Count. 9 SCULL, a shoal or multitude of fish. (No longer used.) 10 BANK, to cause a mound or bank by their numbers. 11 DROPT, sprinkled or variegated. 12 TER-RES'-TRI-AL, belonging to the land. 6 GEN-ER-A'-TION, production of inhabitants. 13 VI'-TAL, life-sustaining. 7 FRY, a crowd of small fish. 8 SHOAL, a multitude. 14 DO-MES'-TI-CA-TED, kept in a tame state. 15 HÄUNTS, retreats; places of resort. 1. LESSON II. THE PHYSIOLOGY1 OF FISHES. "OUR plenteous streams a various race supply: 2. The natural history of fishes treats of their structure and form, their habits and uses, and their classification. By the term fish we are to understand an animal that has a spinal column or back-bone, and that lives in the water; that has a naked body, or a body covered with plates or scales; that moves commonly by means of fins; that breathes by means of gills instead of lungs; that has a single instead of a double heart; and that has cold instead of warm blood. 3. If these are the characteristics of fishes, we see the reason why such animals as whales, dolphins, porpoises, seals, and some others, although they live in the water, are not fishes; for all of them breathe by lungs; they have a double heart like that found in man and all the mammalia; and they are warm-blooded. They are therefore included among the mammalia, and have already been described by us in the first great division of Natural History." 4. The blood of fishes generally assumes the temperature3 of the element in which they live. The red blood disks are sometimes circular and sometimes oval; but they are larger than those of the mammalia and birds, and smaller than those of reptiles. But the cold blood of fishes circulates through their bodies, and performs the same office as the warm blood in man-that of building up and repairing the body, and removing its waste and worn-out particles. 5. Fishes, the same as warm-blooded animals, need to have their blood purified by the oxygen1 of the air; and they are so formed as to be able to obtain from the air which is in the water a quantity of oxygen sufficient for this purpose. Their gills, which are placed on each side of the forward part of the body, answer the place of lungs. Here are spread out innumerable blood-vessels, which receive the blood from the heart; and as the water which the fish takes in at the mouth is driven through the gills, the oxygen which it contains passes into the blood, and thus accomplishes the object for which all animals breathe. 6. If by any means the gill-covers, or openings, are kept closed for a short time, the fish will die for want of air to purify the blood, the same as man dies when the air is excluded from his lungs. A fish will die very quickly in the water when its mouth is kept open by a hook, for it can not then cause the water to circulate through the gills; the gillcovers then close, and the air is prevented from reaching the blood. The angler often avails himself of a knowledge of this principle to suffocate or drown a strong fish. When a fish is taken out of the water, it opens and shuts its mouth and raises the gill-covers alternately; but as the arches which support the gills collapse, and it can not raise them without the aid of water, the situation of the fish is similar to that of an air-breathing animal inclosed in a vacuum, and death by suffocation is the consequence. 5 7. The importance of fishes, as a source of national wealth, renders their geographical distribution a matter of interest and importance; and this seems to be determined by laws quite similar to those which regulate the distribution of land animals. Climate evidently exerts an important influence in regulating the distinctions of form and color between fishes of tropical and those of temperate regions: some species are found only in deep water, and others in shallows; some in fresh, and others in salt water; while, even in the sea, extensive reefs, and even great depths, so effectually divide even kindred species, that the fishes of the coast of the Atlantic States are for the most part distinct from those on the European side of the Atlantic. 8. In the classification of fishes two great divisions are made, the entire class being divided into the two great groups, the BONY and the CARTILAGINOUS. The fishes having bony skeletons are then subdivided into the two classes, the Spine-rayed and the Soft-rayed—the former having some of their fins furnished with simple bony rays, like spines; and the latter having the fin rays soft and flexible. Fishes may therefore be grouped in three great classes: 1st, the Spinerayed Bony Fishes; 2d, the Soft-rayed Bony Fishes; and, 3d, the Cartilaginous Fishes. The latter have the skeleton com posed of gristle or cartilage instead of bone.* 1 PHYS-I-ŎL'-O-GY, the science which treats 3 TEM'-PER-A-TURE, degree of warmth. of the functions of the different parts or or-4 ŎX'-Y-GEN. See p. 269; and Fourth Readgans of animals or plants. er, p. 53. 2 CHAR-AC-TER-IS'-TIES, peculiar qualities. 5 COL-LAPSE', fall together; close. * In treating of fishes we have chiefly followed the arrangement of Cuvier, because most. works on Ichthyology accessible to students adopt this system, and it is one that is easily understood. The new classification of Agassiz, however, as it better accords with the order of succession which is found to exist in the course of geologic history, will doubtless eventually be adopted in most scientific treatises, and thus some knowledge of both systems will be desirable. Agassiz arranges fishes, in accordance with the peculiar structure of the scales, in the following four orders, a system which is applicable to the fossil as well as the living forms. 1st. PLACOIDS-embracing those which, to a cartilaginous skeleton, unite a skin that is covered irregularly with enameled plates or scales, often elevated in the middle, and sometimes with a strong projecting point or spine, as the shagreen on the skin of the sharks, and the tubercles of the rays. Fossils abundant, but existing species few. 2d. GANOIDS-embracing all, whether cartilaginous or not, that are covered by a nearly continuous armor of angular scales of enameled bone, or bony plates that fit to each other as the slates on a roof. Examples-sturgeons and gar fish. In a past geological era the ganoids existed in vast numbers, but they have almost entirely disappeared from creation. 3d. CTENOIDS-fishes whose scales consist of plates having their posterior edges pectinated or comb-like, such as perches. This is a very large division of existing species. 4th. CYCLOIDS-fishes whose scales are entire, and of circular form, as in the salmon, trout, shiners. Also a very large division. The The Ctenoids and Cycloids comprise nearly nine tenths of all existing species. earliest fossil fish, first appearing near the close of the transition period (see Geology, p. 464), were all Placoids. Next in order were the Ganoids, which first appear in the lower strata of the secondary period (see Geology, p. 466). These two latter orders comprised, for untold ages, so far as is yet known, all the fish that existed. In the latter part of the secondary period (see p. 468) the Ctenoids and Cycloids were ushered in. Dorsal The Common Pike-Perch, Lucioperca Americana. In describing a fish, the size, form, and color are given-the number, character, and position of the fins-and frequently the shape and character of the scales, the character of the gills, and the number of the gill-openings. The most important and easily recognized of these features are the fins; and in describing them the names are given, and the number of spines or rays in each. In the above fish-the Common Pike-Perch of the Great Lakes and Western waters (often, but improperly, called the Pike, or Pickerel)-the fins are briefly described as follows: D. 14-1, 22; A. 1, 11; C. 17; P. 15; V. 1,5; the letters denoting the names of the fins, and the figures the number of spines. There being, in the above fish, two divisions of the dorsal fin, it is designated as D. 14-1, 22; showing that the first dorsal has 14 rays, all spinous; in the second dorsal 1 spinous, and 22 that are soft; A. the anal fin, with 1 spinous ray, and 11 that are soft; C. the tail or caudal fin, 17 rays; P. pectoral fin, 15 soft rays; V. the ventral fin, with one spinous ray, and 5 that are soft. FIRST CLASS OF FISHES. SPINE-RAYED BONY FISHES. (Acanthopterygii.)* THE PERCH FAMILY.-1. American Yellow Perch, Perca flavescens. 2. Striped Sea-bass, Labrax lineatus. 3. Black Bass, or Black Perch of Lake Huron, Huro nigricans. 4. Growler, or White Salmon of Virginia, Grystes salmoides. 5. Black Sea-bass, Centropistes nigricans. 6. Mediterranean Apogon, Apogon trimaculatus. 7. Two-banded Diploprion, Diploprion bifaciatum. 8. One-spotted Mesoprion, Mesoprion uninotatus. 9. Ruby-colored Etelis, Etelis carbunculus. 10. Armed Enoplossus, Enoplossus armatus. 11. Lettered Serranus, Serranus scriba. 12. Spined Serranus, Serranus anthias. 13. Red Surmullet, Mullus barbatus. LESSON III. THE PERCH FAMILY. (CTENOIDS.) 1. THE spine-rayed bony fishes comprise more than three fourths of all the various kinds that are known. From fourteen to seventeen different families, some of them embracing several hundred species each, have been included in this division. At the head of the whole stands the Perch family, the most numerous of all. Most of them are salt-water fish, but about one fifth of the whole number inhabit fresh-water streams, or occasionally ascend them from the sea. A-CAN-THOP-TER-Y&'-II, from two Greek words, acanthos, a thorn, and pterugion, a little wing or fin, meaning thorny or spine-rayed. The fishes of this order are distinguished by having the anterior portion of the dorsal, or of the first dorsal where there are two, supported by spinous rays consisting of single bony pieces. Spinous rays are also found in the anal, and at least one in the ventral fins. |