The True Sharks 



559 



sand ; oSovs, tooth) would indicate. The way in which the 

 jaws lie indicates that these teeth belonged to rays rather than 

 sharks. Numerous species have been described, mostly from 

 the Subcarboniferous limestones. Archcrobatis gigas, perhaps, 

 as its name would indicate, the primeval skate, is from the 

 Subcarboniferous Hmestone of Greencastle, Indiana. Teeth 

 of numerous species of Psammodiis and Copodus are found in 



^ 



Fig. 350. — Devil-ray or Sea-de^al, Mania lirostris (Walhaum). Florida. 



many rocks of Carboniferous age. Psammodiis rugosus com- 

 mon in Carboniferous rocks of Europe. 



Family Mobulidae. — The sea-devils, Mobididcc, are the mightiest 

 of all the rays, characterized by the development of the anterior 

 lobe of the pectorals as a pair of cephalic fins. These stand 

 up like horns or ears on the upper part of the head. The teeth 

 are small and flat, tubercular, and the whip-like tail is with 

 or without spine. The species are few, little known, and in- 

 ordinately large, reaching a width of more than twenty feet 

 and a weight, according to Risso, of 1250 pounds. When har- 

 pooned it is said that they will drag a large boat with great 

 swiftness. The manta, or sea-devil, of tropical America is 



