298 Memoir Sears Foundation for Marine Research 



of snout, its anterior margin with a short, blunt-tipped, finger-like lobe near the inner 

 corner. Mouth ovate, about % to % (60 to 83%) as high as broad, occupying about % 

 of breadth of head. Labial furrow extending around corner of mouth and onto each jaw, 

 the upper furrow averaging a little more than % as long as the diameter of eye,° the lower 

 averaging about % as long as upper. 



Teeth usually i^=^=^, similar in the 2 jaws, except that the lowers are a little smaller 

 than the uppers, with triangular cusp; median upper tooth and ist lower tooth usually 

 erect, symmetrical and smaller than those on either side, but those along sides of jaws 

 increasingly oblique toward corners of mouth ; inner margins slightly concave, outer mar- 

 gins deeply notched about midway toward base, with the basal sector strongly convex, the 

 edges smooth, or at most slightly wavy, basally, on the outer side} the lOth to 12th succes- 

 sively smaller than 2nd to 9th. 



First dorsal originates about over inner corner of pectoral when latter is laid back or a 

 little anterior to it, the midpoint of its base varying from a little nearer to axil of pec- 

 toral than to origin of pelvics to a little nearer to the latter than to the former, its ante- 

 rior margin only weakly convex, apex subacute, its posterior margin moderately concave 

 basally, its free rear corner slender and a little more than V3 as long as its base, its rear tip 

 over, or a little anterior to, origin of pelvics. Second dorsal on an average only about Vs 

 as long at base as ist, relatively lower, its apex broadly rounded, its free rear tip much more 

 slender and elongate, being about i V2 times as long as its base, its origin about over, or a 

 little posterior to, midpoint of base of analj the distance from rear tip of 2nd dorsal to 

 precaudal pit about i V4 to i Vs times as long as diameter of eye. Caudal about V4 of total 

 length, with moderately raised axis, narrowly rounded tip and deep subterminal notch, its 

 terminal sector about V3 the length of fin, its lower anterior corner forming a definite tri- 

 angular lobe with subacute tip, a little more than Vs as long as the upper, each measured 

 from the respective precaudal pit. Anal similar to 2nd dorsal in shape, but averaging about 

 I V2 times as long at base, hence considerably larger in area. Pelvics a little longer at base 

 than anal, with nearly straight anterior margins, weakly concave distal margins, rounded 

 apices and subacute tips. Pectoral only about as long as length of ist dorsal along its outer 

 margin and smaller than the latter in area,' a little more than V2 as broad as long, its 

 anterior margin weakly convex, distal margin nearly straight toward tip but moderately 

 concave toward inner corner, the latter subacute, the apex more rounded. 



Color. Brownish to olive-gray above, white below and along rear margins of pec- 

 torals; dorsals and caudals more or less dark-edged, the 2nd dorsal and lower lobe of 

 caudal the most widely so, especially in small specimens. 



Size. Commonly these sharks are about 26 to 30 inches long when mature, rarely 

 growing much larger than 36 inches, the greatest length definitely recorded for a West 



6. Average 82 per cent; extremes 64 and 1 10 per cent. 



7. In most of the Carcharhinidae the pectoral is considerably longer than the ist dorsal, and larger in area. 



