366 Bulletin 4j, United States National Museum. 



the preseuce of a filameutous nasal tip. Length 30 inches. (Goode «fc 

 Beau.) Aho taken oft' San Pedro, California. (Gilbert. Albatross Coll.) 

 {])rocerus, tall or long.) 



Nettastuma procerum, GooDK & Bean, Bull. MuB. Comp. Zoiil., x, ISSii, 2'21, Gulf Stream. 

 Venefica proeera, Jordan & Davis, Apodal Fishes, G52 ; Goode & Bean, (Jceanic Ichth., 149, 18'J5. 



Family L. NEMICHTHYID^. 



"(The Snipe Eels.) 



Body excessively slender, not strongly compressed, deepest near the 

 middle, tapering backward to the tail, Avhich usually ends in a long and 

 slender filament, and forward to a very long and slender neck, which is 

 abruptly enlarged at the occipital region. No scales. Lateral line repre- 

 sented by one or more rows of pores. Head resembling that of Tylosuriis, 

 the head proper small, short, and rather broad, with Hat top and vertical 

 sides. Nostrils large, close together in front of the eye, without tube or 

 flap; jaws excessively prolonged, almost needle-like, the upper the longer 

 and somewhat recurved. Teeth in both jaws small, very numerous, close- 

 set, retrorse. Gill openings rather large, running downward and forward, 

 separated by a narrow isthmus or partly confluent. Pectorals well devel- 

 oped. Anal fin beginning near the vent, higher than the dorsal, becom- 

 ing obsolete on the caudal filament. Dorsal beginning close behind 

 occiput, its anterior rays soft, succeeded by a long series of very low, 

 simple, spine-like rays, which are slightly connected by membrane, their 

 height rather less than the length of the interspaces ; on the tail these 

 spines again give place to soft rays. The soft rays of the fins are con- 

 nected by thin membrane instead of being imbedded in thick skin, as in 

 eels generally. Color translucent, the lower parts dark, the back pale. 

 Stomach not distensible. Muscular and osseous systems well developed. 

 Abdominal cavity extending far behind the vent. Genera 6, species about 

 10; singular inhabitants of the deep seas. The species are little known 

 and their anatomy has not been studied. They are certainly eels, and 

 their nearest relations seem to be with the Nettantomidw. The truncate 

 tail of some specimens is probably a result of mutilation. {Murwrndce, 

 group, Nemichthyina, Gunther, Cat., viii, 21, 1870.) 



a. Gill openings partly confluent, rather large ; vomerine teeth conspicuously enlarged. 



b. Vomerine teeth lancet-shaped, very close set ; jaws moderate, the snout not longer 



than rest of head ; vent at a distance behind head about equal to postorbital part 



of head ; eye above angle of mouth. Serrivomeu, 167. 



/>/>, Vomerine teeth conical ; jaws very long, attenuate ; color silvery. Svinivomeu, 1(J8. 



aa. Gill upenings distinctly separate ; vomerine teeth moderate ; jaws excessively attenuate, 



the ujjper longer and recurved; tail probably always normally with a filiform tip; 



(truncate in injured specimens ; short and band-like in translucent larva"). 



c. Vent remote fiom the head, at a distance behind pectoral more than 3 times length 



of that fin ; color black. 



d. Gill slits lateral, vertical, well separated ; dorsal commencing above pectorals; 



tail filamentous ; jaws long and slender ; a single series of pores along 



lateral line. Avocettina, 169. 



cc. Vent at the throat, at a distance liehind the head less than length of pectoral; 



anal fin beginning below middle of pectorals ; body very long and slender, 



most of tho dorsal rays very slender, nearly free, appearing like slender 



spines ; jaws very slender, not exiiauded at tip. 



