70 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — IV. 
Dasieatis IIASTATA. 
Trfigon hdstata DeKay, New York Fauna, Fish. p. 375, pi. 65, fig. 214 $ . 
Tryyon haniata Storer, Syn. Fish. N. Amer. p. 261. 
Trfjyon hastata Dum^nl, Elasmobraiich. p. 592. 
Disk quadrangular, about oiie-fourtk wider than long ; anterior mar- 
gins nearly straight, meeting in a blunt angle on the end of the snout, 
(jurved near the outer angle to meet the slightly convex posterior mar- 
gins ; inner borders convex ; outer and hinder angles rounded. Y en- 
trals almost entirely covered by the pectorals, hinder margins convex. 
Tail more than one and a halftimes the length of the disk, low-keeled 
on the upi^er side, a long, broad membranous expansion below, rough- 
ened with small asperities, one or more serrated spines. Body smooth 
in young, very old with scattered small asperities. A row of narrow 
compressed tubercles along the middle of the back and on the base of 
the tail ; the points of these tubercles are depressed and directed back- 
ward. On each shoulder, parallel with the median, there is a shorter 
row, the length of which varies according to the age of the individual. 
Alouth with three papillte. Jaws with more curvature than those of 
ccntrura and less than those of sabina. Young without tubercles. 
Color bluish or olivaceous brown, darker on dorsum and tail, liglft on 
lower surface. Measurement of a young specimen : length of disk 8.5, 
wddth 10, and length of tail 14 inches. An adult male measured 20 
inches across the pectorals and 16 in length of body. The museum con- 
tains specimens from Florida, Cuba, Pernambuco, and Bio Janeiro. 
Dasieatis erevis. 
(Garmaii, IS80, Bull. Mus. Comp. Zool. vi, 171.) 
Disk quadrangular, a little wider than long. Anterior margins nearly 
straight, curved near the outer extremities to meet the convex posteriors, 
meeting in a blunt angle on the end of the snout. Outer and posterior 
extremities of pectorals round, without trace of angles. Ventrals broad, 
truncate, with angles rounded. Tail less than one and a half times the 
length of the disk, tapering to an acute point, depressed as far as to the 
spine, thence compressed to the end of the cutaneous fold, and round 
from this point to the tip, with a short elevated membraneous expansion 
behind the spine, and a longer and wider one on the lower side, extend- 
ing below the former and the spine. The expansions have their hinder 
extremities opiiosed ; they end quite abruptly and are widest near the 
