338 



FISHES. 



Teeth obtuse, granular, the dental surfaces of the jaws being 

 undulated. 



Fig. 125. — Dentition oi Ilhynchohatiis. 



Two species, Eh. ancylostomus and Rh. djeddensis, are very 

 common on the tropical coasts of the Indian Ocean. They 

 feed on hard-shelled animals, and attain scarcely a length of 

 8 feet. 



Rhinobatus. — Cranial cartilage produce<l into a long rostral 

 process, the space between the process and pectoral fin being- 

 filled by a membrane. Teeth obtuse, with an indistinct trans- 

 verse ridge. Dorsal fins without spine, both at a great distance 

 behind the ventral fins. Caudal fin without lower lobe. 



Numerous on the coasts of tropical and sub-tropical seas ; 

 about twelve species. Trygonorhina is an allied genus from 

 South Australia. 



The oolitic genus Spathohatis is scarcely distinct from 

 Eliinohatus ; and another fossil from Mount Lebanon has 

 been actually referred to this latter genus. Trigorhina from 

 Monte Postale must be placed here. 



Third Family — Toepedinidj?:. 



The trunk is a hroad, smooth disk. Tail vnth a longitudi- 

 nal fold on each side ; a rayed, dorsal fin is generally, and a 



