388 Memoir Sears Foundation for Marine Research 



Range. Tropical and warm-temperate waters on both sides of the Atlantic. In the 

 west obscurus is reliably recorded from southern Massachusetts and Georges Bank to 

 southern Florida, Louisiana, and the Bahamas; and as far south as southern Brazil by name. 

 In the eastern Atlantic reports apparently referable to obscurus include the Mediterranean 

 coast of Spain,"* Madeira, Senegal, the Canaries and Cape Verdes, as well as the vicinity 

 of Sierra Leone, Ascension Island, St. Helena, and Table Bay, South Africa.*" But final 

 decision as to whether or not the "obscurus" of the two sides of the Atlantic are identical 

 must await comparison of specimens from the two ocean areas. 



Occurrence in the Western Atlantic. Obscurus has been characterized repeatedly in 

 the past as common or even very common along the coast of the United States from 

 New Jersey to Cape Cod. However, it has been proved recently that most of these reports 

 were actually based upon C. milberti (p. 374) or on leucas in some instances, and that 

 North Carolina records of obscurus similarly refer either to limbatus or to Negafrion 

 brevirostris.^^" In fact, it is only around southern Florida that positively identified speci- 

 mens of obscurus have been taken recently in any numbers. Along southwestern Florida 

 it is present in winter, while off the southeastern coast it is common throughout the year. 

 Also, it has been taken off the coast of Louisiana (one specimen, see Study Material, p. 

 383), but is not reported otherwise from the western waters of the Gulf of Mexico. To 

 the northward its distribution presents a puzzling picture, for we find no reliable record of 

 it anywhere along the coast between Florida and Delaware Bay. But it has been taken off 

 the mouth of Delaware Bay and repeatedly on the coast of New Jersey, at Long Island, 

 New York and at Woods Hole, where twelve specimens have come into our hands in recent 

 summers, six of them during August 1944 (see Study Material, p. 383) in addition to 

 others reported in earlier years. There is at least one record for Nantucket and another for 

 Georges Bank, which, while by name only, seem referable to this species and not to milberti 

 because of the large sizes of the specimens in question (11 to 12 feet). However, these 

 last appear to be the most northerly and easterly of the reliable records of the species on 

 this side of the Atlantic, for while obscurus has been reported by name at three localities 

 in the Gulf of Maine,"* at least one of these records"" was almost certainly based on 

 Prionace glauca (p. 282), and the others probably were the same. Also, reliable reports 

 from New Jersey northward rest on odd specimens only, showing that the numbers of in- 

 dividuals that visit any part of the coast north of Florida are very small as compared with 

 milberti, although printed references to "obscurus" for Long Island and for southern New 

 England would suggest the reverse. Its recorded appearances in the northern part of its 

 range are limited to the warm months, chiefly August and September. 



Information on its occurrence south of Florida is even more scanty, i.e., nominal 



121. Carcharhtnus commersonii Rey (Fauna Iberica Feces, r, 1928 : 342), identifiable as obscurus by the presence of a 

 mid-dorsal ridge, position of first dorsal and teeth. 



122. A stuffed specimen in South African Museum (Barnard, Ann. S. Air. Mus., 31 [i], 1925: 26). 



123. Radcliffe, Bull. U.S. Bur. Fish., 5.^, 1916: 255, 257. 



124. Bigelow and Welsh, Bull. U.S. Bur. Fish., ^o (i), 1925: 30. 



125. Storer, Mem. Amer. Acad. Arts Sci., N. S. 9, 1867: 219, pi. 36, fig. 2. 



