'°%l'''] proceedings of the national museum. 351 



Pectoral two-sevenths length of head. Dorsal beginning in advance 

 of gill-opening, its distance from tip of snout slightly less than half 

 distance from snout to anal. 



Uniform light-brownish. Fins dusky, jet-black near tip of tail, where 

 they have a narrow bright white margin. Mouth, gill cavity, and peri- 

 toneum black. 



The type is a single specimen, lOi inches long, taken at Station 2792, 



in 401 fathoms. A second small specimen was obtained at Station 



2799. 



Ophisonia niacrurum, sp. nov. 



Snout comparatively short and heavy, blunt and broadly rounded, 

 projecting but little beyond the lower jaw ; lips full. 



Teeth in mandible in a broad band, those of outer series strong and 

 obviously larger than those of inner series. Maxillary and vomerine 

 teeth also in broad bands, none of the former enlarged, some of the 

 anterior and middle vomerine teeth corresponding in size to the outer 

 series in mandible. Vomerine patch divided by a transverse groove 

 into which tits the tip of the mandible. Xo teeth on shaft of vomer. 



Posterior nostril an elliptical slit on level of upper margin of pupil. 

 Anterior nostril a round pore near tip of snout. Tip and lower margin 

 of snout with five large slit-like mucous pores on each side, the last one 

 under the posterior nostril. 



Gape extending slightly beyond pupil, 2f in head. Eye moderate, 

 three fourths of snout, 6 in head, the diameter of pupil equal to width 

 of interorbital space. 



Head 1^ in trunk (without head), 4 in tail, the latter therefore, nearly 

 twice the length of body. Depth one-tifteenth of total length. 



Pectorals- one-third of head, the fold from upper edge of gill-slit at'- 

 tached to its base below. Origin of dorsal slightly behind base of 

 pectorals, its distance from tip of snout one-half that from tip of snout 

 to front of anal. 



Color dusky above, the under side of head and abdomen white, the 

 two areas separated by a well-defined line. Fins dusky, becoming 

 black towards tip of tail, with a well-marked whitish border. Inside 

 of mouth, gill-cavity, and peritoneum silvery. 



A single specimen, 9i inches long, from the Gulf of California, Sta- 

 tion 3015. 



Ilyophis gen. nov. (Ilyophidae. ) 



Body scaly. Pectorals developed. Lateral line prominent. Gill- 

 slits horizontal, inferior, well separated. Xostrils lateral, the posterior 

 immediately in front of eye, the anterior with a short tube, near tip of 

 snout. 



Maxillaries as in SynaphobranchuSj the clamping processes closely 

 appressed to the side of the vomer behind its head. Lower jaw strong, 

 apparently with the coronoid process well developed. Series of teeth 



