58 PROCEEDINGS OF THE ACADEMY OF [April, 



first dorsal ly\; front margin of second dorsal 2f ; front margin of 

 anal about 3; front margin of lower caudal lobe 2h; least depth of 

 caudal peduncle 6i; pectoral If; ventral 2^^. Body rather well com- 

 pressed, back elevated, edges rather rounded or convex, a very slight 

 median keel down back and a slight median depression down post- 

 ventral and postanal regions. Caudal peduncle slender, well com- 

 pressed, and its least depth about f its length. Head broad, depressed , 

 profiles similar, and when viewed above rather narrowly convergent 



Fig. 1. — Mustelus mento Cope. (Tj^ie 



with rounded tip. Edges of snout rather trenchant, and its length 

 equal to its greatest width. Eye elongate, and its center a trifle 

 posterior in length of head. Mouth moderately broad, symphysis 

 falling but a trifle before front of eye, and rami would form a right 

 angle. Lips thin and little free. At each corner of mouth a pointed 

 flap, free behind and with a rather long outer fold. Teeth pavement- 

 like, in about 50 series. Upper buccal fold papillose, with a slightly 

 ragged margin, not entire as stated previously, and narrow. Lower 

 buccal fold entire. Tongue rather pointed, its upper surface very 

 finely asperous, and margins free. Nostrils large, inferior, well 

 separated, about last third in snout measured to eye, and each 

 with a well-developed flap. Interorbital space convex. Body 



