/OOLOGY. 019 



will still be left, which should correspond to the Fishes, 

 Reptiles, Birds, and Thricozoa, so that no place is left 

 remaining for the Sharks. Now, however, the Salmons 

 correspond decidedly to the Reptilia ; and the Flying 

 Fishes, which are ranged below the Pikes, probably to 

 the Birds. If we unite them with the Herrings, then 

 the Sharks may occupy the place of the Thricozoa. 



This being preassumed, we can now attempt the classi- 

 fication. The substance or texture of the bones is of 

 such importance, that notwithstanding the separation of 

 the Sharks and their congeners, the other Cartilaginous 

 Fishes must be left along with them, and range upon the 

 lowest stage, so that they thus correspond to the Intes- 

 tinal animals. 



The next great distinction in the osseous system is the 

 regular and irregular form which it imparts to the body, 

 so that the Regular -shaped can be separated in a tole- 

 rably "tranchant" manner from the Irregular Fishes. 



The regular form of a Fish is obviously the ellipse, as 

 we find to be the case in our fresh-water Fishes, namely, 

 the Perches, Salmons and Carps. They are collectively 

 covered with large scales, which is therefore also a sign 

 of their regularity. 



The Irregular Fishes are cylindrical, fusi- clavi- spheri- 

 and tubuliform, usually destitute of scales or covered 

 with plates, scutes, and spines. Thus, since the Carti- 

 laginous Fishes are collectively irregular in form, the Irre- 

 gular Osseous Fishes must be allowed to follow them. 



The greatest variety of the osseous system is shown in 

 the limbs, especially the posterior pair, which in the 

 other classes also are generally imperfect and make their 

 appearance the last. In Fishes they are not divided into 

 digits, but only into rays, which probably correspond only 

 to the digital ungues or to feathers. An animal which 

 has fin-rays is assuredly a Fish, for fin-rays do not occur 

 in any Reptile. 



The posterior fins change even their situation. Those 

 Fishes in whom they are placed near to the anus, are 

 obviously the more perfect, as the Ab dominates. 



