15^ CLASSIFICATION OF FISHES. 



fishes ; and both agree in having only one small external 

 branchial opening. The other peculiarities of ChimcBra 

 relate to its three affinities — on one side to Acipenser^ 

 on another to the Raidcs, and on a third to the Plecto- 

 gimthes, — all of which will be noticed in their proper 

 place. 



(135.) Such are the analogies, resulting from our 

 following closely the line of affinity j, and upon which 

 we rest our belief that the five types of the cartilaginous 

 order represent the five great divisions of the class 

 Pisces : but on a question of such paramount importance 

 to the philosophic naturalist, it appears necessary to take 

 a still wider range ; and^ by looking to the whole circle 

 of Tertebrated animals, endeavour to test the correctness 

 of this series by bringing it into comparison with the 

 great groups of the Vertehrata. The resemblances, of 

 course, will be far more remote, because the dissimilar- 

 ities are immeasurably greater j but yet, if our arrange- 

 ment is true to nature, these resemblances_, however 

 faint some may think them, must not only exist in part, 

 but must follow each other in an harmonious and defi- 

 nite order. Placing, therefore, the contents of both 

 groups in separate columns, we shall find some of the 

 analogies both curious and interesting. 



Analogies of the Vertebrata and the Cartilaginous 



Fishes. 



Circle of the Chon- , , . Circle of the 



DROPTERTGEs. Analogies. Vertebrata. 



c 7-j CPartakinemostof all tothe struc-7 nT,.,^r,T,„„T.„ 



Sqiiah(LB. I j^^g ^f^j^g ^^^^^^^_ Viviparous, j Quadrupeds. 



T, -J f Pectoral fins assuming the form 7 ■tj,^^,, 



^'^«^- i of wings. All oviparous. j Birds. 



r Posterior part of the body, or the ■^ 

 Chim^ridee. -5 tail, gradually attenuated and > Reptiles. 



C pointed. 3 



p^ . ., CMost aberrant in their respective? .,.„.„„, . 



Stunoni<LB. | ^j^^i^. Teeth none. j Amphibia. 



Polyodonid^. [ ^Sed!"^ ^^'^ ^^'^^ ' ^'^' ^ ] ^'^''^^■ 



(136.) The following points of analogy do not admit 

 of much illustration, seeing that they are remote ; and 



