396 BULLETIN 10 0, UNITED STATES NATIONAL MUSEUM 



smaller to posterior, first rather more than half width of spiracle. 

 Spiracle oblique, equals eye. 



Disk smooth above except 2 pairs of spines above front part of 

 eyes and 4 over posterior portions; several minute spines on upper 

 eyelid; tail with several rows of spines, largest anteriorly, most 

 numerous posteriorly; both dorsals covered with minute spines. 



Dorsals subequal, interspace about half base length, first dorsal 

 3 in head to spiracle ; no caudal ; pectorals form circular disk, edges 

 all rounded ; front ventral lobes well extended. 



Pale brown above with lighter patches covered with small brown 

 dots. Body, fins, and tail with numerous small bluish spots, absent 

 only on lighter patches of disk. In places bluish spots confluent and 

 form reticulations. Lower surfaces slate colored. Length, 454 mm. 

 (McCulloch.) 



South Australia, Southwest Australia. 



Family DASYATIDAE 



Body, head, and pectorals depressed, forming wide disk. Tail 

 distinct from disk, narrow and tapering, usually with serrated spine. 

 Mouth transverse, more or less curved. Teeth small, in quincunx, 

 tessellated. Front nasal valves confluent across narrow isthmus, 

 reaching mouth. Gill openings narrow. Spiracles large, close be- 

 hind eyes. Front copula of hypobranchial cartilages segmented. 

 Skin smooth or rough with spines or tubercles, or both. Pectorals 

 meet in front of cranium, forming snout without supporting rostral 

 cartilages. Ventrals small, below pectorals. 



A large family with many species, living mostly in the seas and 

 rivers of subtropical or tropical countries. They are generally found 

 in bays, lagoons, or inlets in shallow water. As they conceal their 

 bodies by burying in the mud or sand leaving only their eyes and 

 spiracles free, they are a scourge to the unwary bather or fisherman, 

 for should one be trodden on it immediately darts its murderous 

 caudal spine into the foot or leg of its victim, inflicting painful or 

 even mortal wounds. Sting rays are said to fling their tails around 

 fishes they attack for food, piercing or tearing at them with the 

 deadly caudal spine, much the same as they would try to defend 

 themselves from a powerful enemy. 



ANALYSIS OF GENERA 



a^. Dasyatinae. Disk about wide as long. 

 6^. Tail long and whiplike. 

 &. Tail with serrated spine. 



(i\ Disk oval ; tail compressed Taeniura 



d". Disk quadrangular; tail filamentary Dasyatis 



(?. Tail without serrated spine; disk circular., „ iTrogyninus 



