162 OSTEOLOGY OF SYNAPHOBKANCHIDJi GILL. 



ous vertical fins, pectorals well developed, scaly skin, and nearly perfect 

 branchial skeleton.* 



Description. 



Body slender anguilliform, moderately compressed anteriorly, much 

 compressed toward end of tail, and with the anus in the anterior third 

 of the total length. 



Scales small, linear or elongate elliptical, arranged in small groups 

 obliquely at right angles to those of the neighboring groups. 



Lateral line distinct, more or less high up and on each side of the 

 back in front, but gradually declining, and near the middle behind. 



Head moderate, compressed, oblong, conic laterally, with all the bones 

 invested in the skin. 



Eyes within the anterior half of the head, directed sideways, of mod- 

 erate or large size, covered by thin skin. 



Nostrils lateral, the posterior considerably in advance of the lower 

 half of the eye, the anterior near the tip of the snout and subtubular. 



Mouth with the cleft slightly oblique, extending considerably beyond 

 the eyes. 



Jaws well developed ; maxillines approximated close to the front of 

 the vomer, with the clamping processes selliform and appressed closely 

 to the sides of the vomer behind its head, Avith ledge-like extensions 

 within along the anterior half, and expanding vertically backwards; 

 mandible slender, the dentary with the coronoid process obsolete, the 

 surface of the bone having a corneous appearance behind, ensheathing 

 the articular, which extends well forward in front of the condyle and 

 scarcely at all backwards. 



Teeth conic, in a narrow band in the jaws and vomer. 



Lips obsolete. 



Tongue little developed. 



Periorbital bones almost membranous. 



Opercular apparatus feebly developed ; operculum lamelliform and 

 claviform, inserted very low on the h^^omandibular ; suboperculum ex- 

 panding downwards and with an anterior process continued in front of 

 the operculum ; interoperculuni lamelliform, intervening between the 

 suboperculum and preoperculum ; preoperculum almost reduced to a 

 muciferous canal. 



Branchial apertures inferior and confluent in a single external longi- 

 tudinal slit. 



Branchiostegal rays in moderate number (about fifteen), attached to 

 the sides of the compressed ceratohyal and epihyal, slender, abbrevi- 

 ated, and moderately bowed, not being curved up above the operculum. 



Dorsal, anal, and caudal confluent in an uninterrupted fin, with the 



• If we look to the essential characters, however, rather than to those which will 

 enable the group to be recognized in comparison with the other families as readily 

 as possible, the family cau be defined as enchelycephalous apodals with abbfeyiate^ 

 "branchiostegal rays and single ventral branchial apertufe. 



