350 Memoir Sears Foundation for Mari?ie Research 



Developmental Stages. Embryos nearly ready for birth closely resemble their parents 

 except that the lower tailfold is relatively narrower. A female gave birth to three young 

 on capture. ^^ Other females that gave birth to four or five, one of them also containing 

 15 eggs of various sizes, likewise have been referred to this species. ^'^ Nothing further 

 is known of its breeding habits. 



Habits. All recorded captures of this Ray have been from partially enclosed waters, 

 or at least from close inshore. The fact that all dated records of it from North Carolina 

 to New Jersey have been during the months of July, August and early September 

 shows that it is a summer visitor to the northern part of its range. But reports of its 

 northerly presence have not been numerous enough for us to establish the approximate 

 dates of its vernal arrival or of its autumnal departure, or to afford a correlation between 

 its migrations and the seasonal cycle of temperature. 



The stomachs of Florida specimens ^^ and of others collected near Beaufort, North 

 Carolina, contained clams, blue crabs {Callinectes), shrimps, worms, and small bony 

 fishes. Specimens which we opened at Bimini, Bahamas, contained stomatopods, 

 shrimps, crabs, worms, and fish. Further information as to its way of life is confined 

 to an observation among the Florida Keys that they are usually seen gliding in pairs 

 close to the sandy bottom from which it is difficult to distinguish them, and that they 

 swim away rapidly upon the approach of a small boat.^* They are reported as being 

 sometimes taken on hook and line as well as in seines on the bottom around Trinidad. 

 And the fact that a specimen, referred to this species, towed a 22-foot launch for 15 

 minutes '^^ illustrates the power with which the larger Sting Rays drive ahead when 

 disturbed. 



Numerical Abundance. No precise information is available as to its actual abundance 

 anywhere except that it is common on the coasts of Mississippi and western Florida,^^ 

 that 20 were taken in the vicinity of Beaufort, North Carolina, in 1936 between July 30 

 and August 16,^' and that we saw five specimens brought in at Bimini by one fishing 

 boat on one day in January 1949. 



Relation to Man. Adult individuals, being even greater in size than Dasyatis say., 

 are doubtless as great a menace as the latter to anyone haneiling or treading upon them, 

 but no specific reports have been received of injuries inflicted by this particular Ray. 



Range. Coastal waters of the western Atlantic, from Rio de Janeiro, Brazil to 

 New Jersey. 



Details of Occurrence. In early scientific literature D. americana was often con- 

 fused with the larger Z). centroura of more northerly habitat, and there are many pub- 

 lished reports of its presence by name without any supporting evidence as to actual 

 identity. Hence it is hazardous to define its distribution from the published record 

 alone. Our Study Material, however, includes specimens from localities so distributed 



51. Radcliffe (Bull. U.S. Bur. Fish., 34, 1916: 274, pi. 46, fig. 3) shows mother and young. 



52. Coles, Bull. Amer. Mus. nat. Hist., 28, 1910: 338; Fowler, Monogr. Acad. nat. Sci. Philad., 7, 1945: 99- 



53. Personal communication from Stewart Springer. 54. Fowler, Proc. Acad. nat. Sci. Philad., 5S, 1906: 80. 

 55. Gudger, Aust. Mus. Mag., 6 (6), 1937: 208. 56. Personal communication from Stewart Springer. 

 57. Fowler, Monogr. Acad. nat. Sci. Philad., 7, 1945: 99. 



