428 yE W FISHES FROM PA CIFIC OCEAN— GILBERT cj- CRAMER, vol. xix. 



HYMENOCEPHALUS ANTR^EUS, new species. 

 (Plate XLVI, fig. 2.) 



Head of to Oi; depth 8 to Sh; B. 7. First dorsal I, to 1. 11: inrto- 

 rals 13 to 10; veutrals 12. 



Head large, squarish, its cavities greatly developed, roofed over by 

 very thin membrane; the bones very thin, translucent and He.xible. 

 Sides of head vertical; snout very short, bluntly rounded, with slightly 

 projecting niediau ])oint, below which the profile is vertical; snout 

 ahout 2 m vertical diameter of orbit, luterorbital space flat, H in ver- 

 tical diameter of orbit, 3^ to 3§ in head. Orbits and nostrils with 

 prominent bony rims; most of head covered by a translucent integu- 

 ment, the shrinkage of which makes the bones unduly prominent. 

 Mouth terminal, not overpassed by snout, somewhat oblique, the lower 

 jaw included ; maxillary reaching beyond hinder edge of orbit, 2 in head. 

 Teeth small, in very narrow villiform bands on both jaws. Those on sides 

 of lower jaw sometimes in a single series. Orbit very large, its horizon- 

 tal diameter 2?^ in head, its vertical diameter 2.^ m head, its up})er edge 

 entering the i»rotile. Angle of preopercle rounded, its posterior edge 

 vertical. Barbel wanting or excessively minute. Gill membranes 

 united in front, uot attached to isthmus. First gill slit nearly equal to 

 diameter of orbit. Body moderately compressed, its M'idth about two- 

 thirds of the depth. Tail very slender. Trunk and tail tapering 

 almost uniformly from head to tip of caudal. Scales very deciduous, 

 large, very thin and flexible, cycloid, smooth; about 5 rows between 

 lateral line and origin of first dorsal. The scales that were still in 

 place were very few, but the above descrii)tion applies to scales studied 

 in position on the shoulder, on the back in front of first dorsal, on 

 up])er part of side below first dorsal, on lateral line, and on belly 

 behind the base of the ventrals. Second dorsal spine smooth. Base 

 of first dorsal equal to interorbital space; distance between dorsals 

 about equal to twice the base of first dorsal. Pectorals very narrow 

 and slender, 1^ in head. Base of ventrals under i)ectorals, rays 

 slender, the outermost elongated into a filament reaching much beyond 

 origin of anal. Distance from tip of snout to origin of anal about 3f 

 in total. Vent far back, just in front of origin of anal. Distance from 

 vent to istlnnus at least as great as length of head. 



Color {in alcohol). — Tiunk dark brown; tail light, marked with 

 darker brown; a line of dark-brown dots along axis of tail and a dark 

 mark at the base of each ray of anal and second dorsal fins. Jaws, 

 breast, and belly to origin of anal, intense black; sides of head and 

 trunk silvery, washed with blackish. Gular membrane translucent, 

 with a network of brown lines; lateral portions of isthmus, and a 

 streak extending from them posteriorly above base of ventrals, silvery, 

 crossed by extremely tine parallel brown lines, hardly to be distin- 

 guished without the aid of a lens. Base of first dorsal dusky, fins 

 otherwise pale. Inside of mouth dusky or blackish. Peritoneum 



