346 Bulletin 41, United States National Museum. 



i. Pectoral fins well developed ; skin thick ; skeleton 

 firm ; Biiout moderate ; tail not ending in a 

 filiform tip. Mur.tinesocid.t:, xlviii. 



H-. Pectoral fins wholly wanting ; snout and jaws 

 much produced, the upper longer ; jaws 

 straight ; skin thin, the skeleton weak ; tail 

 ending in a filiform tip ; gill openings small, 

 Eubinferior: teeth shar]i, subequal, recurved; 

 a long series on the vomer ; deep-sea eels, 

 soft in body, black in color. 



KETTASTOMID.E, XLIX. 



ij. Jaws long and slender, tapering to a point, recurved 

 at tip ; nostrils large, both pjiirs close in front of 

 eye ; gill openings convergent forward, separate 

 or confluent ; pectorals and vertical fins well 

 developed ; membranes of fins thin, not envelop- 

 ing the rays ; skeleton well developed ; deep-sea 

 eels. Kemichthtid.t;, t. 



gg. Posterior nostril close to the edge of the upper lip ; tongue more 

 or less fully adnate to the floor of the mouth ; teeth subequal. 



Mtrid.i:, lt. 

 ff. Tip of tail without rays, projecting beyond the dorsal and anal fins (not 

 filiform) : posterior nostril on the edge of the upper lip ; anterior 

 nostril near tip of snout, usually in a small tube ; tongue usually 

 adnate to the floor of the mouth. Coloration frequently varie- 

 gated. Ophichthyid^, lu. 



COLOCEPHALI : 



aa. Gill openings small, roundish, leading to restricted interbranchial slits ; tongue wanting; 

 pectoral fins (typicall3') wanting : opercles feebly developed ; fourth gill arch modi- 

 fied, strengthened, and supporting pharyngeal jaws. 

 /. Scapular arch obsolete or represented by cartilage ; heart not far back ; pectorals want- 

 ing ; skin thick ; coloration often variegated. Mcbj:nid.e, liii. 



Suborder ENCHELYCEPALI. 

 (The Eels.) 



The characters of this group are given al)Ove. {h/xi^^v?} eel ; KEcpaX?'/, 

 head. ) 



Family XLIII. ANGUILLTD.E. 

 (The Truk Eels.) 



The true eels or Anguillida; are characterized by their scaly skin in 

 association with a conical head and a general resemblance to the Congers. 

 The group is thus diagnosed by Dr. Gill : 



Enchelycephalous Apodals ^^ith conical head, •u-ell-developed opercular 

 apparatus, lateral maxillines. cardiform teeth, distinct tongue, vertical 

 lateral branchial apertures, continuous vertical fins, with the dorsal far 

 from the head, pectorals well developed, scaly skin, and nearly perfect 

 branchial skeleton. 



The AnguiUidte approach more nearly than most of the other eels to the 

 type of the true fishes. In one respect, that of the minute ova and con- 

 cealed generation, however, they differ widely from these. The single 

 genus of living AtiguiUidce is widely diffused in temperate and tropical 

 waters. Unlike the other eels the Anguillida' freely ascend the rivers, 

 descending to the sea for purposes of reproduction. One genus, with 5 or 

 more valid species. [Murdnidw, genus AuguiUa, Guxther, Cat., viil,23 

 to 37, 1870.) 



a Dorsal fin inserted well behind base of pectorals, shoulder girdle well developed ; lower 

 jaw projecting. Angcilla, 150. 



