PISCES. 



11 



animals/ and likewise that the water in which they 

 live is proved to be a good medium. Fishes, parti- 

 cularly of the skate kind, have a bag at some di- 

 stance behind the eyes, which contains a fluid, and 

 a soft cretaceous substance, and supplies the place 

 of the vestibule and cochlea: there is a nerve di- 

 stributed upon it, similar to the portio mollis in man: . 

 they have semicircular canals, which are filled with 

 a fluid, and communicate with the bag : they have 

 likewise a meatus externus, which leads to the in- 

 ternal ear. The cod-fish and others of the same 

 shape, have an organ of hearing somewhat similar 

 to the former, but instead of a soft substance con- 

 tained in the bag, there is a hard cretaceous stone. 



The cuticle in Fishes is strong and thick, and is 

 defended by an armature of scales, closely laid over 

 each other: the generality of Fishes have a particular 

 line or series of small ducts running along each side 

 of the body, and discharging a soft mucus or slimy 

 substance, serving to lubricate the surface of the 

 body. 



The fins of Fishes are named from their situation 

 on the animal, viz. dorsal or back-fin, pectoral or 

 breast-fins, ventral or belly-fins, anal or vent-fin, 

 and caudal or tail-fin. 



The ventral fins are considered by Linnaeus as 

 analogous to the feet in quadrupeds, and it is from 

 the situation, presence, or absence of these fins that 

 the Linnasan orders of Fishes are instituted v 



Such as are entirely destitute of ventral fins are 

 termed Pisces apodes, being, as it were, apodal or 

 footless Fishes. Those which have the ventral fins 



