BT ALLAN R. MCCDLLOCH. 



4U3 



along the mediau line of the back, each of which is armed with a stout depressed 

 spine worn smooth on its upper surface; the first is midway between the eyes 

 and the scapular region; three more are in advance of the scapular region, and 

 three others are close together in the middle of the back. A single small spinate 

 tubercle is present on the right side of the scapular region. 



Text-fig. 1. fJnder surface of the tail of Dasyatis thelidis, from off Norah Head, New 



South Wales, 20-40 fathoms. 

 Text-fig. 2. Under surface of the tail of Dasyaiis brevicaudaius , from the same 



locality. 



Tail depressed before, cylindrical behind the spine, its length from the 

 middle of the vent 0.44 longer than the body. A row of tubercles armed with 

 large spines commences on the median dorsal line in advance of the margins 

 of the ventrals, but the rest of the tail is smooth anteriorly; smaller spinate 

 tubercles appear on the sides and upper and lower surfaces well in advance of 

 the spine, and become more and more numerous backwards. A low cutaneous 

 and minutely spicular fold commences slightly in advance of the insertion of 

 the caudal spine, and extends backward to the end of the tail; it is deepest 

 anteriorly where it is about one-fourth a'^ deep as the tail above it, and 

 decreases gradually backward. 



Eyes very small, the space between them eiiual to the greatest width be- 

 tween the spiracles; they are 4.2 in the bony interorbital space, which is 

 slightly more than half the preorbital length. Spiracles very large, longer than 

 broad, their length 1.5 in the interorbital width. 



The space separating the nostrils is 1.3 in their distance from the end of 

 the snout. Outer angles of the internasal lobe rounded : a narrow flap is folded 



