N0.1239. APODAL FISHES OF JAPAN— JORDAN AND SNYDER. 841 



kk. Pectoral iins wholly vvantinis;; snout and j;i\vs ituicli ym- 

 duced, the upiKT lonj^er; jaw strai<j;ht; skin Ihin, tiie 

 skeleton weak; tail endinjj in a filiforni tip; gill openings 

 small, snhinferior; teeth sharp, suhequal, recurved; a 

 long series on the vomer; deep-sea eels, soft in body. 



NeTTASTOMIDvE. VI. 



gg. Posterior nostril clo.se to tlie edge of the upper lip; tongue more or 

 less fully adnati' to the floor of the mouth; teet^i subequal. 



Mykid.e. VII. 



ff. Tip of tail witlu)ut rays, projecting beyond the dorsal and anal fins, 



(not filiform) ; posterior nostril on the edge of the upjier lij); anterior 



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



adnate to the floor of the mouth. Coloration frequently variegated. 



OPHICHTHYIDiE. VIII. 



ee. Tail nuich shorter than the trunk; heart situated at a great distance 

 behind the gills; pectorals small or wanting; vertical fins little devel- 

 oped; body slender, cylindrical; gill openings narrow, inferior. 



MORINGUID/E. IX. 



an. Colocepluili: Gill openings small, roundish, leading to restricted interbranchial 

 slits; tongue wanting; pectoral fins (typically) wanting; opercles feebly devel- 

 oped; fourtli gill arch modified, strengthened, and sujiporting pharyngeal 

 jaws. 

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

 wanting; skin thick; coloration often variegated MuR^NiDiE. X. 



Family II. ANGUILLID^E. 



TRUE EELS. 



The true eels, or AngulJIlihe^ are characterized by their scaly skin in 

 association with a conical head and a t^eneral resemblance to the Oon- 

 ger-'i. The group is thus diagnosed l)y Dr. Gill: "" Enchelycephalous 

 Apodals with conical head, well-developed opercular apparatus, lateral 

 maxillines, cardiform teeth, distinct tongue, vertical lateral branchial 

 aperttires, continuous vertical fins, with the dorsal far from the head, 

 pectorals well developed, scaly skin, and neai'ly perfect branchial 

 skeleton,"' 



The Angidllidw 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 concealed generation, however, they differ widely from these. 

 The single genus of living AnguillidcB is wideW difi'used in temperate 

 and tropical waters. Unlike the other eels the Angu'dUdoi freely 

 ascend the rivers, descending to the sea for purposes of reproduc- 

 tion. One genus, with five or more valid species. 



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

 lower jaw projecting \ AnguiUa. 2. 



