556 



The True Sharks 



rounded disk, and a stout, short tail with a caudal fin. It has a 

 strong spine, and for its size is the most dangerous of the sting- 

 rays. Urolophus halleri, the California species, was named for a 

 young man who was stung by the species at the time of its first 

 discovery at San Diego in 1863. Urolophus jamaicensis abounds 

 in the West Indies, Urolophus mundus at Panama, and Urolo- 

 phus fuscus in Japan. None of the species reach Europe. The 

 true sting-ray (stingaree, or clam -cracker) , Dasyatis, is more 

 widely diffused and the species are very closely related. In 

 these species the body is angular and the tail whip-like. Some 



Fio. 348. Sting-ray, Dasyatis sabina Le Sueur. Galveston. 



of the species reach a length of ten or twelve feet. None have 

 any economic value, and all are disliked by fishermen. Dasyatis 

 pastinaca is common in Europe, Dasyatis centrura along our 

 Atlantic coast, Dasyatis sabina ascends the rivers of Florida, 

 and Dasyatis dipterura abounds in the bay of San Diego. Other 

 species are found in tropical America, while still others (Dasyatis 

 akajei, kuhlii, zugei, etc.) swarm in Japan and across India to 

 Zanzibar. 



Pteroplatea, the butterfly-ray, has the disk very much broader 

 than long, and the trivial tail is very short, its little spine more 

 often lost than present. Different species of this genus circle 

 the globe: Pteroplatea maclura, on our Atlantic coast; Ptero- 

 platea marmorata, in California ; Pteroplatea japonica, in Japan ; 



