REVISION OF CARCHARHINID SHARK GENERA — SPRINGER 575 



The appearance of this species is most striking for its comparatively 

 long and greatly depressed snout (snout in front of nostrils is up to 

 7.0 percent of t.l. and almost always more than 5.4 percent). 



The upper labial furrow is developed poorly and exists only as a 

 short crease directed at a right angle from the lower furrow, which is 

 visible when the mouth is closed. 



There is no interdorsal ridge and the lower precaudal pit is essentially 

 obsolete. 



Growth changes (see table 4) : Snout length to outer nostrils, eye, 

 mouth, first gill-opening, pectoral origin, and pelvic origin tend to 

 decrease in percent of t.l. with increased t.l., as do distance between 

 inner nostrils, mouth width, gill-opening lengths, and eye diameter. 

 Height of first dorsal fin, anterior and distal margins of pectoral fin, 

 width of pectoral fin and distance from tip of caudal fin to notch tend 

 to increase with increased t.l. 



In the largest specimens examined the axis of the upper caudal lobe 

 has been raised in relation to the horizontal axis of the body as com- 

 pared with the condition in small specimens (even including mature 

 individuals; see fig. 2). 



Males may mature at about 350 mm. t.l. as determined by what 

 appears to be a fully developed clasper (when the clasper is about 8 

 percent of t.l.). The following tabulation for Scoliodon indicates that 

 claspers gradually increase in proportionate length until the shark 

 reaches about 350 mm. t.l. The clasper lengths then increase abruptly 

 and remain more or less constant in proportionate length until the 

 shark is about 450 mm. t.l. At this point there is a gradual decrease 

 in proportionate clasper length. 



