CHAPTER XLIII 

 INTRODUCTION TO THE CLASS OF FISHES 



The study of fishes is called ich-thy-ol'o-gy. 



So great is the number of species that the mass 

 is, at first thought, fairly bewildering. During 

 the last twenty years the researches of the men 

 who devote their lives to the study of fishes 

 (called ich-thy-ol'o-gists) have brought to light 

 hundreds of new forms. 



The inhabitants of the waters of North Amer- 

 ica, alone, form a great multitude. Of the fishes 

 found north of Panama, marine and inland, the 

 "Descriptive Catalogue" of Drs. Jordan and 

 Evermann, Part IV, completed in 1900, enumer- 

 ates the following groups, species and subspecies 

 as recognized by those authors : 



Orders of Fishes 30 



Families 225 



Genera 1113 



Species ' 3263 



The four volumes comprising the work men- 

 tioned above make a pile nine-and-a-half inches 

 high, and contain 3,313 fine-print pages of 

 text, and 392 plates. The "Systematic Arrange- 

 ment, " or table of contents, is wholly in Latin, 

 a,nd fills 95 closely-printed pages. The work 

 has been carefully devised to be of no use what- 

 ever to anyone save an ichthyologist. 



When this array confronts the general stu- 

 dent, the prospect is rather appalling. From 

 the first page to the last, every technical work 

 on fishes abounds in descriptive terms that to 

 most persons are about as attractive as the 

 spines on a porcupine fish. If the general reader 

 attempts to master them, he soon finds himself 

 involved and discouraged, and the desired gen- 

 eral view of our finny tribes is obscured in fog. 



But the whole subject of fish study is merely 

 a matter of method. With fishes, as with the 

 other vertebrates, the Orders are the master 

 keys by which a proper exhibit can be unlocked 

 and displayed. At the same time, the Subclass 

 divisions 'are of great importance, and must con- 

 stantly be kept in mind. Leaving out the deep- 

 sea fishes, which we can well spare for the pres- 

 ent, there are twenty well-defined Orders, the 

 types of which are almost as easily known and 



375 



remembered as a score of pictures in an art gal- 

 lery. The Orders must not be lost sight of, for 

 when they are firmly grasped by the understand- 

 ing and the memory, the fog begins to rise. 



General Characters. — A typical fish is a 

 cold-blooded animal, with a bony skeleton, an 

 elongated body which is covered with overlap- 

 ping scales, and an outfit of fins for balancing, 

 steering and propulsion. It has gills instead 

 of lungs, fixed eyes, and a swimming-bladder, 

 and is specially fitted for a wholly aquatic life. 

 It is provided with teeth, it hears sounds by the 

 transmitting power of the bony plates of the 

 skull, and usually it lays eggs for the production 

 of its young. The body of a typical fish is wedge- 

 shaped, narrowest at the tail, thin from side to 

 side, and the head tapers to a blunt point. This 

 form is specially designed for rapid and easy 

 progress through water. 



The Black Bass jnay fairly be regarded as a 

 perfectly typical fish. 



The variations from the perfect type are al- 

 most innumerable. For example: 



The Lung-Fish has foot-like fins, and practi- 

 cal lungs. 



The Catfish has no scales. 



Some Sharks and a few other fishes bring forth 

 their young alive. 



The Rays and Skates are the flattest of all 

 vertebrates. 



The CHmting Perch can cUmb. 



The Flying-Fish can rise from the sea, and fly. 



The Lantern Fish, of the deep sea, carries a 

 phosphorescent Ught upon its head. 



The anatomy of fishes is a special branch of 

 knowledge in which the general reader can 

 scarcely be concerned, but for the young ich- 

 thyologist there are many special works. Books 

 for the identification of all the known spemes 

 of fishes in North America are now available 

 for those who desire them. At present, how- 

 ever, we are concerned only with the twenty 

 great groups, or Orders, and the fifty or sixty 

 important types which represent them. Of 

 these there must be some serious study. 



Up to this date, nearly every systematic writer 



