1908.] NATURAL SCIENCES OF PHILADELPHIA. 67 



or robust, greatest depth about origin of dorsal, and edges of body- 

 depressed or flattened. No very evident pits at origins of caudal lobes. 

 Caudal peduncle rather robust, scarcely compressed, and its least 

 depth 1^ in its length. 



Head moderately large, well depressed both above and below and 

 with evenly convex surfaces. Snout rather broadly depressed and 

 moderately short, as viewed from above front margin undulate with a 

 median emargination where tip would form . Each side of head produced 

 laterally into a very narrow^ long depressed hammer-like process with its 

 front margin much thicker than posterior, also former as viewed above 

 a little undulate in profile while posterior is nearly straight. Along 

 anterior margin of each hammer a rather deep groove, extending from 

 nostril half-way to median point of snout and distally to end of hammer. 

 Eye at anterior external lateral extremity of hammer, elongate, rather 

 small, and its horizontal diameter about 4-^ in distal expansion of 

 hammer. Nictitating membrane broad, conspicuous, and evidently 

 leaving a deep pocket on each side. Mouth broad, margin of upper 

 jaw rather evenly lunate or convex, and ramus of mandible would 

 form a very obtuse angle. Gape of mouth about f its width. No 

 groove at each corner of mouth. Teeth all moderately large, directed 

 laterally, entire, rather broadly triangular, and each with an external 

 notch, no basal cusps. About 28 series of teeth in upper jaw and 

 about 24 series in lower. Nostril inferior on hammer along its anterior 

 margin near basal fifth of latter, as measured along its posterior margin, 

 or about inner f of space between tip of snout and end of hammer. 

 Nostril furnished with but a slight flap. Top of head rather broadly 

 convex. 



Gill-openings, first a little nearer posterior margin of hammer basally 

 than origin of dorsal, last two over base of pectoral, and second and 

 third largest. No spiracle. 



Body covered entirely with very minute shagreen denticles of appar- 

 ently uniform size. On lower surface of hammer anteriorl}^ a number 

 of more or less conspicuous small pores. 



Origin of first dorsal nearer tip of snout than that of second or about 

 opposite first fifth in space between origin of pectoral and that of 

 ventral, fin high, falcate, apex forming above just behind its base 

 which is If in its height, and its posterior point about 3f in head. 

 Origin of second dorsal a little nearer that of first dorsal than end of 

 last caudal vertebra or about over middle of base of anal, base of fin 

 about I of its total length and long posterior point 3f in head. Origin 

 of anal a little nearer posterior basal margin of ventral than origin of 



