536 



SHARKS AND RAYS. 



the rays in the same particular. Each contains but a single existing genus, and 

 the first is unknown previous to the present epoch. 



Side-Giiied The four species belonging to the first family, one of which 



Saw-Fishes. (Pristioplwrus japonicus) is shown in the illustration, are com- 

 paratively small fishes confined to the Japanese and Australian seas. Having the 

 body scarcely depressed, and the pectoral fins of moderate dimensions, and not 



angel-fish ( T \; nat. size). 



extending forwards to the head, these saw-fishes are distinguished by the lateral 

 position of the gill-clefts, and full development of the so-called prepalatine 

 cartilage, and the presence of a pair of long tentacles on the lower aspect of the 

 jaw. J n habits these fishes probably resemble those of the next genus. 



Distributed over all the warmer seas, the members of this genus, 

 among which Prisiis antiquorum of the Mediterranean and Atlantic 

 is most commonly met with, differ from the last, not only in the inferior position 

 of the gill-clefts, but likewise in the small development of the prepalatine 



True Saw-Fishes. 



