Fishes of the Western North Atlantic 337 



Relation to Man. Such specimens as are caught in the Florida fishery (see below) are 

 used for leather, etc., like other large sharks. 



Range. It is known to the present time from the south coast of Cuba (see Study 

 Material, p. 333) and the north coast near Havana," Porto Rico, and southeastern 

 Florida. Hence it probably occurs generally throughout the tropical belt of the western 

 Atlantic. Evidently it is plentiful locally, for it is taken so frequently in the shark fishery 

 that is now carried on from Salerno, Florida, that it has been given the vernacular name 

 "Silky Shark," appropriate because of the small size of its dermal denticles. As many 

 as 60 adults of nine to ten feet were caught there in a single day during the winter of 

 1943, making it dominant in the total catch of sharks of all sorts for the time being. It is 

 less numerous there in summer.^' That a shark so common, so large and so easily recognized 

 should have continued unknown for so long casts an unflattering light on scientific knowl- 

 edge of the group to which it belongs. 



Synonvins and References: 



Carcharkinus jalcijormis (in part) Evermann and Marsh, Bull. U.S. Fish Comm., 20 (l), 1902: 6?. (meas., 



Porto Rico, one of two specimens, the other being correctly identified as C. falciformis Muller and Henle, 



1841). 

 Carcharinus foridanus Bigelow, Schroeder and Springer, Proc. New Engl. zool. CL, 22, 194.3: 71, pi. 13 (ill., 



descr., Salerno, Florida, type loc, and south coast of Cuba). 

 Eulamia fioridanus Bigelow and Schroeder, Guide Comm. Shark Fish., Anglo ."^mer. Caribb. Comm., Wash., 



1945: 76, fig. 22 (descr., range, ill.), 



Carcharhinus leucas (Muller and Henle), 1841" 



Cub Shark, Bull Shark, Ground Shark 



Figures 60, 61 



Study Material. Female, 924 mm. long, from Florida (Amer. Mus. Nat. Hist.)j 

 skin of a female, about 1,137 mm-j at Miraflores Locks, Panama Canal (U.S. Bur. Fish., 

 No. 1 3961); headof specimen, about 6 /'o feet, from Bahamas (from Daniel Merriman); 

 embryo, 435 mm. long, from Cuba (Harv. Mus. Comp. Zool., No. 722)} tracings of 

 fins of an adult male, 2,310 mm., from Metacumbe, Florida (from Stewart Springer); 

 male embryos, 490 mm. (Harv. Mus. Comp. Zool.) and 625 mm. (U.S. Nat. Mus., No. 

 108,456), from Englewood, Florida; female, 692 mm. long, either embryo or newborn to 

 judge from the umbilical scar, also female, 920 mm., from Lake Yzabal, Guatemala (U.S. 

 Nat. Mus.). 



Distinctive Characters. Leucas is separable from all other Atlantic carcharhinids 

 except Negaprion brevirostris, Carcharhinus longimanus and C. nicaraguensis by its ex- 



17. Personal communication from Luis Howell-Rivero. i8. Personal communication from Stewart Springer. 



19. The account of leucas by Miiller and Henle (Plagiost., 1S41: 42) agrees in detail with the present species, 

 except that the dried specimens on whicli it was based were described as white above as well as below. But their 

 paleness (probably from fading) was perhaps exaggerated, for the same specimens (presumably) were described 

 later as whitish gray (Dumeril, Hist. Nat. Poiss. /, 1S65; 35S). 



