114 



THE PLAGIOSTOMIA. 



dorsal smaller and the hind border more nearly vertical. The cusps of the teeth 

 appear to be longer and more slender in S. lalandii than in either of the others 

 mentioned. 



Total length of an adult male from Rio Janeiro 23, snout to abdominal 

 pores 11, snout to fifth gill opening 5?, and snout to mouth ll inches. 



Off the eastern coasts of South America. Hassler Expedition. 



SCOLIODON LONGURIO. 



Carcharias (Scoliodon) longurio Jordan & Gilbert, 1882, Proc. U. S. nat. nius., 5, p. 106. 

 Scoliodon longurio Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 42. 



Head long; snout more pointed than that of S. lalandii, the nearest ally; 

 nostrils at nearly one third of the distance from the mouth to the end; distance 

 between nostrils equal their distance from the end of the snout, which equals 

 the length of the mouth. Mouth large, broad, broadly arched in front, length 

 equal two thirds of the width; labial folds extending about one third of the 

 length on each jaw. Teeth in fi rows; bases broad; cusps turned toward the 

 angles of the mouth above a notch on the outer border. Median tooth, and the 

 two symphyseal teeth of the lower series smaller, more erect. The teeth cusps 

 in this species appear to be more erect and broader than in either S. lalandii or 

 S. terrae novae. Eye large, pupil vertical. Hind margin of the pectoral slightly 

 indented, inner angle bluntly rounded, outer angle more pointed and slender 

 than in *S. lalandii. First dorsal origin little behind the inner angle of the pec- 

 toral, fin smaller and more deeply excavated behind than in S. lalandii; end of 

 fin not reaching above origins of ventrals by about one length of the orbit. 

 Second dorsal very small, base one fourth of that of the first, two thirds of that 

 of the anal, distant three times its length from the caudal pit. Lobe of sub- 

 caudal deep, rather narrow, blunt. 



Total length 31, snout to pores 152, snout to fifth gill opening 7, and snout 

 to mouth 2l inches. 



Back slaty brown shading to white on the flanks and below; hind margins 

 of pectorals and anal, and front of subcaudal lighter, other margins of caudal 

 darker, all darker on adults. 



Mexico to Panama, in the Eastern Pacific. 



