70 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — IV. 



Dasibatis HASTATA. 



Tn/ffon hastata DeKay, New York Fauna, Fish. p. 375, pi. 65, fig. 214$. 

 Trygon haniata Storer, Syu. Fish. N. Amei'. p. 261. 

 Trtj/joti hastata Diim^ril, Elasmobranch. p. 592. 



Disk quadraugular, about one-fAirth wider than long ; anterior mar- 

 gins nearly straight, meeting in a blunt angle on the end of the snout, 

 curved near the outer angle to meet the slightly convex posterior mar- 

 gins ; inner borders convex ; outer and hinder angles rounded. Ven- 

 trals almost entirely covered by the pectorals, hinder margins convex. 

 Tail more than one and a half times the length of the disk, low-keeled 

 on the upper 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 

 tlie 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. 

 Mouth with three papilljc. 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, light on 

 lower surface. Measurement of a young specimen : length of disk 8.5, 

 width 10, and length of tail 14 inches. An adult male measured 20 

 inches across the pectorals and IG in length of body. The museum con- 

 tains specimens from Florida, Cuba, Peruambuco, and Eio Janeiro. 



Dasibatis brevis. 



(Garman, 1880, Bull. Mns. Comp. Zoiil. 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 j^osterior 

 extremities of pectorals round, without trace of angles. Yentrals broad, 

 truncate, with angles rounded. Tail less than one and a half times the 

 length of the disk, tajiering 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 opposed;, they end quite abruptly and are widest near the 



