68 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — IV. 
the outer extremities ; posterior convex ; inner straight a portion of their 
length. Ventrals truncate, rounded. Snout produced, forming a 
rounded prominence in front of the margins of the disk. Length from 
the forehead less than the width of the head. A line joining the wider 
l)ortions of the disk passes nearer to the head than to the shoulders. 
Tail more than twice as long as the body, without a trace of lieel above ; 
a long narrow expansion below has its origin opposite that of the spine, 
and terminates in a keel which continues to the extremity, roughened 
with small tubercles, with an irregular series of broad-based conical 
tubercles on each side. A pair of large, compressed, erect tubercles 
stands immediately in front of the caudal spine, and a similar one is 
j)]aced over the middle of the ]>elvic arch. These suggest a continuous 
series in larger specimens. Three larger elongated tubercles, with 
points directed backward, similar to those of Z>. hastata, occupy the mid- 
dle of the shoulder girdle. Mouth curved, six (5-G?) papillreat the bot- 
tom behind the teeth ; two of these are in the middle in front, where 
usually there is but one. Color light olive, probably greenish in life, 
white below. Distinguished from ]>. centnira by the prominent snout, 
the shape of the tubercles in the middle of the back, and the narrowness 
of the posterior portion of the »lisk. Length of body 10, tail 35.3, and 
width of pectorals 20.5 inches. Sent from the Sandwich Islands b}’ 
Andrew Garrett. 
DASIBATIS SABINA. 
Trygon sahina Losnenr, .Tonr. Acad. Nat. Sci. Phil, iv, p. 109. 
Triigoii sahina Miill. ct Heule, Plaginstomen, p. 1G3. 
Trijgon sahina Dum6ril^ Elasmobraiicli. p. 607. 
Disk subcircular. Snout produced, blunt. Anterior margins of the 
pectorals concave near the snout, becoming convex toward the broadly 
rounded outer extremities ; hinder and inner margins convex. Up]>er 
jaw with a deep indentation, receiving a corresponding prominence on 
the lower. Teeth at the sides of tins indentation much larger, resem- 
bling the molars of Jleferodontuft. Mouth with five papilhn. Tail less 
flian twice as long as the disk, tapering to a tine point, rough with small 
inickles similar to those scattered over the head and back, a cutaneous 
expansion above, and a broader, longer one below. These end nearly 
opposite each other, the loAver extends forward under the spine. AVitli 
a median roAV of tubercles on the dorsum and one or a pair on each 
shoulder. Distinguished from tuherculata by the shape of the snout, the 
rounded pectorals, the shorter tail, the larger teeth, the greater curva- 
