490 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 41. 



PENTANCHUS Smith and Radcliffe, new genus. 



The characters of the genus are sufficiently indicated in the family 

 description. 



Genotype. — Pentanchus profundicolus. 



PENTANCHUS PROFUNDICOLUS Smith and Radcliffe, new species. 

 Plate 42. 



Form very elongate and slender, back not elevated, body tapering 

 gradually into the long, slightly decurved tail; body and caudal 

 peduncle much compressed; head long, broad, moderately depressed, 

 length of head (to posterior gill-opening) .25 total length, width of 

 head at angle of jaws equal to snout, depth .3 length; depth of caudal 

 peduncle three times its thickness and .6 length of base of dorsal fin; 

 eye superior, rather small, the length of orbital opening equal to dis- 



PENTANCHUS PROFUNDICOLUS. UNDER SIDE OF HEAD. NATURAL SIZE. 



tance between inner angles of nostrils, vertical diameter of eye less 

 than width of cheek; snout very long, broad, and flat, slightly dilated 

 at nostrils and tapering acutely from nostrils to the rounded tip, 

 length of snout equal to distance from anterior margin of eye to 

 second gill-opening, its width at nostrils .75 length, length of tapering 

 side equal to distance to posterior corner of eye, under surface of 

 snout flat, the upper and lower sides of snout forming a sharp edge, 

 the preoral space more than .8 length of snout; mouth wide, cres- 

 centic, the jaws somewhat protruding, anterior margin of mouth 

 entnely anterior to eye, the angle of mouth under pu])il, a well- 

 marked groove at angle extending more than .7 distance to nostril 



