56 



considerably elongated, that with their aid, the 

 animal can sustain itself for some time in the 

 air* The ventral fins, as their name denotes, 

 are placed on the lower or under part of the fish. 

 Their situation, however, is not uniform, for we 

 find them either near the mouth, on the chest, or 

 on the belly. Thus we have the jugular es^ of 

 which the haddock is an example, where the 

 ventral fins are placed before the pectoral fins, 

 or under the throat ; the thoracini, as the perch, 

 where they are placed on the breast, immediate- 

 ly under the pectoral fins ; and the abdominales, 

 as the salmon and perch, where they are placed 

 on the belly, behind the pectoral fins. The anal 

 fin is placed between the anus and caudal fin or 

 tail, which is situated at the extremity of the 

 body ; arid which is variously shaped, and serves 

 to form distinctive characters by which fish are 

 divided and arranged in classes, genera and 

 species. 



The fins themselves are formed of skin, stretch- 

 ed or extended on osseous or cartilaginous rays, 

 and united to the body by means of certain pe- 

 culiar bones. The pectoral or ventral fins alone, 

 however, can be said to correspond to the upper 

 and lower extremities of the higher classes of 

 animals. They are acted on by several muscles 

 admirably adapted to the necessities of the ani- 

 mal. Thus we find in the pelagian tribes, which 

 traverse the ocean contending with waves and 

 currents, large and strong fins furnished with 

 powerful muscles ; while those which delight in 



