lis CLASSIFICATION OF FISHES. 



CHAP. VI. 



ox THE ORDER CARTILAGINES, OR CAETILAGINOUS FISHES. 



(104.) The cartilaginous fishes, at the head of which 

 stand the sharks and rays^ are well known to be the 

 largest and the most formidable of the whole class. The 

 pecuhar structure of their skeleton, which gives rise to 

 their name^ admits of these animals continuing to grow 

 as long as they Hve ; the consequence of which is, that 

 as they inhabit the wide ocean^ and have few enemies, 

 they are sometimes met with of such an enormous size, 

 that their weight and dimensions are almost incredible. 

 Besides these two families, numerous both in minor 

 divisions and species, we include the sturgeons, the 

 spoon-fish {Spatularia of Shaw), and those extraordi- 

 nary fish, the ChirnoerincE, or sea-monsters. 



(lOo.) The distinguishing anatomical characters of 

 this order consist in the skeleton or bones being en- 

 tirely cartilaginous ; that is to say, it is not formed of 

 osseous fibres, but the calcareous matter is deposited in 

 small grains, and not by filaments : hence it is that 

 there are no sutures in their skull, which is always 

 composed of a single piece ; the usual divisions, how- 

 ever, of the cranium of ordinary fishes may, in these, 

 be readily distinguished by the angles, hollows, and 

 other inequalities on the surface of the cranium. It is 

 remarkable, also, that the moveable articulations in the 

 other orders are here not at all apparent. As an in- 

 stance of this, it may be mentioned, that a part of the 

 vertebrse of certain rays (Raia) are united into a single 

 body; while, in other instances, some of the articula- 

 tions of the bones of the face, according to Cuvier, dis- 

 appear. The most apparent anatomical characters of 

 this class is, to want the maxillary and inter-maxillary 



