48 



CETACEOUS FISH. Class IV, 



viz. two peroral fins, and one back fin j but in 

 fome fpecies the laft is wanting. 



Their tails are placed horizontally or fiat in re- 

 fpect to their bodies - 9 contrary to the direction of 

 thole of all other fifh, which have them in a per- 

 pendicular fite. This fituation of the tail enables 

 them to force themfelves fuddenly to the furface of 

 the water to breathe, which they are fo frequently 

 conftrained to do. 



Many of thefe circumftances induced Linnaus to 

 place this tribe among his Mammalia, or what other 

 writers ftyle quadrupeds. 



To have preferved the chain ' of beings entire, 

 he mould in this cafe have made the genus of 

 Thoca, or Seals, and that of the Trichecus or 

 Manati, immediately precede the whale, thofe be- 

 ing the links that connect the Mammalia or qua- 

 drupeds with the fifh ; for the Seal is, in refpect 

 to its legs, the moft imperfect of the former clafs ; 

 and in the Manati the hind feet coalefce, aflum- 

 ing the form of a broad horizontal tail. 



Notwithstanding the many parts and properties 

 which cetaceous fifh have in common with land 

 animals, yet there flill remain others, that in a 

 natural arrangement of the animal kingdom, mud 

 determine us after the example of the illuftrious 

 Ray *, to place them in the rank of fifh ; and for 



* Who makes two divifions of filh. 



1. Pulmone refpirantes. 



2. Branchiis refpirantes, 



the 



