374 Memoir Sears Foundation for Marine Research 



and 1-2 on each shoulder; halfgrown specimens and older likewise develop an increas- 

 ing number of low rounded tubercles along median belt of head from a little anterior 

 to orbits rearward past level of spiracles, while small prickles appear in increasing 

 numbers along upper and lateral surfaces of tail posterior to spine; large females 

 (apparently not the males) also have a few small tubercles around outer margins of 

 eyes and spiracles; tubercles are also sparsely distributed from nuchal region rearward 

 along median belt of back. Lower surface entirely smooth in both sexes. 



Snout in front of eyes about i. 0-1.4 times as long as distance between outer 

 margins of orbits, its length in front of mouth about 1.9—2.6 times as great as distance 

 between exposed nostrils and i. 0-1.3 times as great as that between inner ends of first 

 gill openings. Eye about 69-76 "/o ^s long as distance between eyes and about equal 

 to or a little longer than spiracle. Nasal curtain with posterior margin moderately 

 concave (in varying degree), its free edge finely scalloped, the individual lobelets short, 

 rounded, mostly simple. Upper jaw conspicuously arched forward in both sexes but 

 projecting a little rearward centrally; lower jaw weakly recessed centrally to fit upper 

 jaw when closed. Floor of mouth with three stout papillae centrally, in transverse row, 

 flanked on either side by one slender papilla (perhaps sometimes by two). 



Teeth 28-36 ^ uppers considerably largest about midway between center of jaw and 

 outer corners, lowers about equally large all along jaw except near outer corners where 

 smaller; those of females and of immature males quadragonal or pentagonal with 

 blunted corners, the functional surface rounded or nearly flat, often more or less scored 

 by wear; those of sexually mature males with long slender cusp except toward corners 

 of mouth; about eight rows in function on upper jaw, 10-12 on lower jaw centrally, 

 and 8—9 toward corners. 



Pelvics with broadly rounded posterior margins, reaching beyond rear limits of 

 pectorals for a distance about as great as length of orbit and spiracle combined;"^ 

 anterior margin about as long as distance from its own origin to rear extremity of pelvic 

 or somewhat shorter. Claspers of mature males stout, with simple tips, reaching rear- 

 ward a little more than halfway from level of axils of pectorals toward origin of tail spine. 



Color. Described"^ as brown or yellowish brown above, paler toward margins of 

 disc, sometimes with a dark stripe along midline of back; upper tailfold yellowish 

 brown, the lower fold buff. Lower surface white on small and medium-sized specimens, 

 but disc of larger ones sometimes margined with gray-black from opposite spiracles 

 to axils of pectorals, with posterior parts of pelvics of same hue; tail underneath white 

 or blotched with grayish anteriorly, dark posteriorly. 



Relationship to Eastern Atlantic Species. So far as the tailfolds are concerned, D. 

 sabina finds its closest affinity with D.pastinaca among Sting Rays of the eastern 



111. In his original account of the species, which is otherwise sufficiently diagnostic, Lesueur (J. Acad. nat. Sci. Philad., 

 4, 1824: 109) describes the pelvics as "long and pointed." Evidently this was an error, for this is not true of any 

 Sting Ray of the western Atlantic except for the recently described Dasyatis geijskesi Boeseman 1948. They 

 were correctly represented by Muller (in Erman's Reise, 1835: pi. 14) in his illustration of his supposedly new 

 Trygon osteostka from Brazil, which in reality cannot be separated from sabina, as Garman (Mem. Harv. Mus. 

 comp. Zool., j6, 191 3: 398) has pointed out. 



112. We have no color notes from life. 



