350 Bulletin 47, United States National Museum. 



snout. Maxillaries as in Synaphobranchus ; 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 on 

 head and shaft of vomer continuous ; no lips ; tongue little developed, 

 with narrow free margin ; branchiostegal rays 15 in number, (as deter- 

 mined without dissection), not shortened, some of them curved around 

 and above the opercle. Dorsal, anal, and caudal confluent, rather high, 

 the rays clearly visible through the skin ; dorsal beginning well forward, 

 its origin immediately behind the base of pectorals ; origin of anal near 

 end of anterior third of body. (At>f, ooze j b<j>ig, snake.) 



576. ILYOPHIS BRUNNEUS, Gilbert. 



Body narrow, compressed throughout ; snout and jaws slender ; gape 

 one-half length of head, extending beyond the eye for a distance less than 

 the diameter of the latter ; maxillary teeth small, bluntly conic, in nar- 

 row bands j teeth on vomer large, conic, those on shaft of vomer in a single 

 row ; teeth in mandible in narrow band, those on the inner series enlarged 

 and retrorse though less than half the size of the vomerine teeth ; front of 

 pupil over end of second third of length of jaw ; gill slits narrow, inferior, 

 horizontal, crescent-shaped, about equaling horizontal diameter of eye, 

 their lower (anterior) ends separated by a distance equal to their own 

 length, their upper (posterior) ends by 1| times that distance ; head 2 in 

 trunk ; head and trunk 3 in total length ; pectorals small, 6 in head, rays 

 evident; scales very fine, arranged in groups at right angles to one 

 another ; lateral line running high anteriorly, its pores white and con- 

 spicuous. Color brown, the fins, lower side of head, and branchial regions 

 darker. (Gilbert.) Length 15 inches. One specimen, from Chatham 

 Island, Galapagos Archipelago, in 634 fathoms, (brunneus, brown.) 



Ilyophis brunneus, GILBERT, Proc. U. S. Nat. Mus., 1891, 352, Chatham Island ; JOBDAN & 

 DAVIS, 1. c., 670. (Coll. Albatross.) 



Family XL VI. SYNAPHOBRANCHID^E. 



This group consists of deep-sea eels, differing from the Anyuillida; in 

 having the gill openings externally confluent into a single slit. The fol- 

 lowing diagnosis is given by Dr. Gill : 



Enchelycephalous Apodals with conic, pointed head, moderate opercu- 

 lar apparatus, lateral maxillines, cardiform teeth, distinct tongue, inferior 

 branchial apertures discharging by a common aperture, continuous ver- 

 tical fins, pectorals well developed, scaly skin, and nearly perfect branchial 

 skeleton. 



Body eel-shaped, covered with linear, imbedded scales placed at right 

 angles, as in Anguilla. Lateral line present. Head long and pointed, the 

 snout produced. Mouth very long, the eye being over the middle of its 

 cleft. Jaws about equal ; teeth small, sharp, in a broad band in each jaw, 

 becoming a single series anteriorly ; those of inner series in upper jaw and 

 of outer series in mandible somewhat enlarged ; vomerine teeth in a nar- 

 row band anteriorly. Gill openings inferior, horizontal, close together, 

 convergent forward, somewhat confluent at the surface, but separated by 

 a considerable isthmus within. Branchiostegals peculiarly formed, in 



