10 CALIFORNIA ACADEMY OF SCIENCES 



between dorsals; base of second dorsal 6f times. Margin of second dorsal gently concave. Front 

 margin low, the angle broadly rounded, barely reaching posterior end of base when fin is declined. 

 The posterior lobe is much produced and acute, slightly longer than base of fin, the latter ij in the 

 distance from its base to front of caudal pit. Upper lobe of caudal 3| in total length; the lower lobe 

 2^ in the upper. Terminal lobe of caudal 3I in the upper lobe. Anal larger than second dorsal, 

 higher, with deeply incurved margin, its base a little longer, its origin slightly in advance of that 

 of second dorsal; the posterior insertions of the two fins nearly opposite. Length of anal base i| 

 in its distance from anterior edge of caudal pit. 



Color bluish above, whitish or grayish below. Free margin of pectorals narrowly white, the 

 anterior edge narrowly bordered with black, which is most evident when seen from the outer surface, 

 the inner surface being dusky. The first dorsal is unmarked, the second dorsal has the anterior lobe 

 dusky. Upper edge of caudal black, the lower margin faintly dusky. Fins otherwise unmarked. 



A single specimen, a female, 120 cm. long, was procured in the Panama mar- 

 ket. As preserved, it is partially skinned. The following measurements were 

 taken when the specimen was intact, hefore preservation. Where not exactly 

 agreeing with dimensions given above, the latter will be found more reliable. 



mm. 



Tip of snout to insertion of dorsal 413 



Base of first dorsal m 



Distance between dorsals 280 



Base of second dorsal 45 



From second dorsal to front of caudal pit 73 



Front of caudal pit to tip of caudal 350 



Tip of snout to axil of pectorals 380 



Axil of pectorals to front of base of ventrals 283 



Front of ventrals to front of anal 165 



Front of anal to front of cautlal pit 116 



Girth at front of first dorsal 451 



7. Carcharias cerdale (Gilbert.) 



Plate II, Fig. 4. 

 Carcharinus cerdale Gilbert, Jordan & Evermann, i8y8, p. 2746. 



Body moderately compressed, not elevated, the depth at front of dorsal not more than one- 

 fourth greater than the oblique anterior margin of the dorsal fin, less than the distance from the nostril 

 to the first gill-slit. Head depressed, the snout flattened, long and narrow, acute. Length of snout 

 beyond mouth \ to ,'„ greater than distance between angles of mouth in all but one (the largest) 

 specimen, where it is slightly less than width of mouth ; -f to f greater than distance from tip of lower 

 jaw to a line connecting angles of mouth; \ to J^ greater than width of snout opposite outer angle of 

 nostrils. Interorbital width equaling distance from tip of snout to front of eye in the young, to middle 

 or posterior border of eye in older specimens; less than half distance to first gill-opening. Middle of 

 eye nearer nostril than angle of mouth by i to | its diameter. Distance from eye to nostril \ or 

 slightly more than \ distance from nostril to tip of snout. Middle of nostrils much nearer front of 

 mouth than tip of snout. Nasal flap with a very narrow, short, acute lobe, placed at end of inner third 

 of flap. Outer angle of nostrils nearly at margin of snout, the inner angles separated by a distance 

 equaling or slightly exceeding that between inner angle of nostril and back of eye. Lips very little 

 developed, the lower entirely concealed in closed mouth, the upper visible as a very short fold. 



Teeth in lower jaw narrow, erect, serrulate on both margins, more coarsely so toward base. 

 The serration is more conspicuous in the smallest specimens (45 cm.), and is obsolescent on some of 



