IGS THE PLAGIOSTOMIA. 



middle of its base, the base of the anal extending but little the farther back. 

 Tail short, less than one fourth of the total length; caudal small, narrow, no pit 

 at its root, tip bluntly rounded, subcaudal followed by a notch, lobe feebly 

 developed. 



Slaty brown, with numerous irregular scattered spots of black on back and 

 flanks. 



Total length 22, snout to abdominal pores 10|, snout to fifth gill opening 4|, 

 snout to mouth I5, and caudal 5 inches. 



Description from specimens taken at Callao, Peru, by the Hassler Expedi- 

 tion. 



Triakis henlei. 



Plate 6, fig. 1-4; Plate 50, fig. 1^. 



Rhinotriacis henlei Gill, 1862, Proc. Acad. nat. sci. Phil, p. 486; Jord. & Everm., 1896, Bull. 47, U. S. 



nat. mus., p. 31. 

 Triakis henlei FvTNAU, 1863, Bull. M. C. Z., 1, p. 14; Duivt^RiL, 1865, Elasm.,p. 398; Jordan & Gilbert, 



1882, Bull. 16, U. S. nat. mus., p. 20. 

 Pleuracromylon laevis Jordan & Gilbert, 1880, Proc. U. S. nat. mus., 3, p. 52. 



Trunk elongate, subtriangular in a cross section, with a low fold above the 

 vertebrae. Head long, depressed, flat beneath, broader than high, little convex 

 on the crown. Snout pointed, blunted at the end, length greater than the width 

 of the mouth. Nostrils in the hindmost third of the preoral length; anterior 

 valve short, rounded, with two internal lobes on the fold dividing the nostril 

 above it. Mouth nearly straight at the sides, rounded in front; labial folds on 

 both jaws w^ell developed. Orbit elongate, length greater than the width of the 

 gill openings; nictitating fold well differentiated. Spiracle small, close behind 

 the eye. Hindmost gill opening narrow, above the pectoral. Teeth small, 

 numerous, compressed, subtriangular, oblique, broad-based; cusps short, sharp, 

 broadening in the base, on each side of which there is usually a notch with a den- 

 ticle. On the inner edge of some teeth both notch and denticle may be absent. 

 Pectorals short and broad, width three fourths of the length, angles rounded, 

 hind margin nearly straight, fin applied to the side reaching behind the middle 

 of the entire dorsal. Dorsal origin little behind the ends of the bases of the 

 pectorals, length of base, much greater than the height, equal to two fifths of the 

 distance from the second dorsal. Second dorsal more than half as large as the 

 first, of similar form, distant more than the length of the base from the caudal. 

 Anal small, hardly half as large as the second dorsal, origin nearly below the mid- 

 dle of the base and end httle farther back than that of the same fin. Caudal one 

 fifth of the total length, subcaudal lobe slightly developed. 



