196 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Leptoeharias smithii Grat, List fish British Museum, p. 51, 1851 (type). — 

 Garman, Mem. Mus. Comp. Zool., vol. 36, p. 164, 1913 (compiled).— Fowler, 

 Copeia, No. 1, p. 21, 1930 (note on identity of Mustelus osborni) ; Bull. Amer. 

 Mus, Nat. Hist., vol. 70, pt. 1, p. 59, fig. 15, 1936 (type of Mustelus osborni). 



Leptocarcharias smithii Gtjnther, Cat. Fishes British Mus., vol. 8, p. 384, 

 1870 (type locality given as "South Africa"). 



LeptocarcJiurias smitM Barnard, Ann. South African Mus., vol. 21, pt. 1, p. 28, 

 1925 (compiled). 



Mustelus osborni Fowler, Amer. Mus. Nov., No. 103, p. 1, 1923 (type locality: 

 Mouth of the Congo). 



Depth 10% to subcaudal origin; head 6%, width II/2. Snout 2 in 

 head ; eye 9%, 4% in snout, 5 in interorbital ; mouth width 2% in head, 

 long as broad; preoral length 1% in mouth; teeth small, alike in jaws, 

 with median longer cusp and 1 or 2 smaller basal cusps, all decreasing 

 in size toward mouth angles ; small median erect lower tooth ; nostrils 

 behind middle in snout length, much closer to mouth than snout end, 

 front valve with long, slender, pointed lobe, internarial I14 in preoral 

 length; interorbital 1% in head, rather low. Gill openings 

 equidistant. 



Scales minute, tridentate, median point longest. 



First dorsal origin opposite depressed pectoral tip, front fin edge 

 equals head measured to second gill opening ; second dorsal front edge 

 very slightly less than head to first gill opening ; anal origin opposite 

 first third of second dorsal base, front fin edge 1% in head ; pectoral 

 11/10, width 13/5 its length; ventral length II/3, slender clasper long as 

 fin ; caudal 4V5 in rest of body, subcaudal 3 in caudal. 



Gray brown, paler below. (Miiller and Henle.) 



West Africa. Barnard gives its length as 550 mm. 



A.M.N.H. No. 8281. Mouth of the Congo. Messrs. H. Lang and J. H. Chapin. 

 Length, 752 mm. Type of Mustelus osT)orm. 



Genus TRIAKIS Miiller and Henle 



Triakis MtJLLER and Henle, Ann. Mag. Nat. Hist. Charlesworth, vol. 2, p. 86, 



1838. (Atypic: Type, Triakis scylUum Miiller and Henle; Syst. Beschr. 



Plagiostomen, p. 63, 1841. Type, Triakis scyllium Miiller and Henle, mono- 



typic.) — Agassiz, Nomenclat. Zool., Index, p. 375, 1846. 

 Triads Gunther, Cat. Fishes British Mus., vol. 8, p. 348, 1870. (Type, Triakis 



scyllium Miiller and Henle. Emendation.) 

 Rhinotriacis Gill, Proc. Acad. Nat. Sci. Philadelphia, 1862, p. 486. (Type, 



Rhinotriacis henlei Gill, monotypic.) 

 Calliscyllium Tanaka, Fishes of Japan, vol. 10, p. 17, 1912. (Type, CaUiscyl- 



lium venustum Tanaka, monotypic.) 

 Hemitriakis Herbe, Philippine Journ. Sci., vol. 23, p. 70, 1923. (Type, Hemi- 



triakis leucoperiptera Herre, monotypic.) 



Body elongate. Head depressed, flattened below. Snout obtuse. 

 Eye small, with nictitating fold. Mouth arched, labial folds and car- 

 tilages well developed. Teeth small, numerous, bases with 2 roots, 

 each tooth with stronger median cusp and at each side of base denticle 



