SHARKS. 



101 



resembles that of the Bipnoids. In fact this Suborder connects [Case 30.] 

 the Ganoids with the Plagiostomes. It contains one family only, 

 represented in the living fauna by two genera — Chirrmra and 

 Callorhynchits. Of the former three species are known — Ch. mon- 

 strosa, from deep water off the coasts of Europe, Japan, and the 



Fig. 90. 



Egg of a Dog-fish (ScyUium). (From Magelhan Straits.) 



Cape of Good Hope; Ch. colliei, off the west coast of North 

 America ; and Ch. affinis, off the coastof Portugal. Callorhynckus 

 antarciicus is common in the southern temperate zone, and differs 

 from the preceding by the curious shape of the snout, which bears 

 a cartilaginous prominence terminating in a cutaneous flap. 



Plagiostomata, or Sharks and Rays. 

 These have from five to seven gill-openings and the teeth are 

 numerous. They differ greatly among each other with regard to 



