360 Memoir Sears Foundation for Marine Research 



As pointed out on p. 357, D. centroura of the western Atlantic is so close to D. 

 aspera (Cuvier) 1 8 1 7 of the Mediterranean, Madeira, and tropical West Africa, that 

 it is an open question whether or not the two are separable. 



Details of Occurrence. Until recently the coast sector from Delaware Bay to Nan- 

 tucket and Cape Cod, Massachusetts, was the only region north of the equator whence 

 reports of the presence of this great Ray were supported by conclusive evidence. Within 

 this sector, however, it is to be expected anywhere in suitable situations. Thus it has 

 been reliably recorded from: Delaware Bay (Green Creek); numerous localities scattered 

 along the New Jersey Coast, from Cape May to Sandy Hook Bay, both along the 

 open beaches and within inlets and bays;^" New York Harbor; Orient at the eastern 

 end of Long Island; Stratford, Connecticut; Narragansett Bay and along the Rhode 

 Island Coast; near Block Island; and the vicinity of Woods Hole. This last locality 

 appears to mark the boundary of its regular occurrence northeastward, for the only 

 definite records of its presence farther east or north are of one specimen from Nan- 

 tucket Island (see Study Material) and another reported from Chatham on the outer 

 coast of Cape Cod, many years ago. Also it is said to have been seen on the shoaler 

 parts of Georges Bank.'i 



To the southward D. centroura is reported from the inner parts of Chesapeake 

 Bay and ofiF the mouth of the latter, but without evidence of actual identity. '^ The 

 most southerly positive record for it is of a specimen taken recently off Cape Hatteras, 

 North Carolina.'^ And it is hardly conceivable that the presence of so large and so for- 

 midable a Ray would not have been reported frequently along the South Atlantic" 

 and Gulf coasts of the United States if it occurred there in numbers at all approaching 

 those that visit the coasts of New Jersey, New York, and southern New England. Nor 

 has it been reported from the West Indian region, from the Caribbean, from the coasts 

 of the Guianas, or from Brazil. 



This seeming absence of D. centroura from the whole tropical-subtropical belt of 

 the western Atlantic in both hemispheres lends special interest to the fact that a similar 

 Ray has been taken recently at Los Pocitos Beach, Mercedes, Uruguay, near the 

 mouth of the Rio Uruguay. According to the published description and illustration, 

 it resembles the northern D. centroura so closely, especially in form of disc, in dermal 

 armature, and in tailfold, that it was recorded as that species (see Range). The latitu- 

 dinal range of D. centroura, with its southern hemisphere counterpart, thus parallels 

 that of the Raja radiata and R. doello-juradoi pair and of the R. spinicauda and griseo- 

 caudata pair among Skates (pp. 255, 275), and of several pairs of Shark species. 



90. New Jersey localities of definite record, south to north, are: Green Creek (on Delaware Bay); Cape May; Sea Island 

 City; off Palermo; Corson Inlet; Somers Point; Beesely Point; Ocean City; Ventnor; Atlantic City; Great Egg 

 Harbor; Beach Haven; Barnegat Inlet; Bradley Beach; Ocean Grove; Long Branch; and Port Monmouth in 

 Sandy Hook Bay. 



91. Bigelow and Welsh, Bull. U. S. Bur. Fish., 40 (i), 1925: 70. It has sometimes been said that its range extends north- 

 ward to Maine (so stated by Jordan and Evermann [Bull. U. S. nat. Mus., 47 (i), 1896: 83], and by some subsequent 

 authors, doubtless upon Jordan and Evermann's authority), but seemingly there is no factual warrant for this. 



92. Uhler and Lugger, Rep. Comm. Fish. Md., ist ed., 1876: 1S7; 2nd ed., 1876: 158. 



93. See Study Material, p. 352; also p. 359, footnote 84. 



94. Early reports of it from South Carolina and from Florida were by name only. 



