Jordan and Evermann. — Fishes of North America, 2887 



upper lip; anterior nostril near tip of snout, iisnally in a 

 small tube ; tongue usually adnate to the floor of the 

 mouth. Coloration fre(iaently variegated. 



LII, Ophiciithyid.k, 372. 

 CC. Gill openings small, roundish, leading to restricted interl)rauchial 

 slits; tongue wanting; pectoral fins (typically) wanting; 

 opercles feebly developed; fourth gill arch modified, 

 strengthened, and supporting pharyngeal jaws. 

 N. Scapular arch obsolete or represented by cartilage; heart not 

 far back; pectorals wanting; (skin thick; coloration often 



variegated) LIII, Mur.enid.e, 388. 



BB. Gill openings far behind cranium; gape of mouth inordinately 

 distensible; gill arches 5 or 6 pairs; tail excessively long, 

 tapering to a point. 

 O. Distance from gill opening to vent much greater than thai from 

 tip of snout to gill opening. 



LIV, SaccopharyngiDvE, 405. 

 00. Distance from gill opening to vent much less than from ti]i of 



snout to gill opening LV, Eurypiiaryxgid.e, 406. 



AA. Premaxillary and maxillary present, often immovably iinited to 

 lest of cranium. 

 P. Gill openings united in a single slit below throat; no pectoral 



fins ; body eel-shaped XLI, Symbranchid^e, 342. 



PP. Gill openings not united in a longitudinal slit. 

 Q. Dorsal fin wanting; anal tin very long; vent near the head; cau- 

 dal obsolete; body band-like XL, Gymnotid^, 340. 



QQ. Dorsal tin present. 

 R. Body eel-shaped, contracted at the neck; the vertical fins con- 

 fluent around the tail ; premaxillary and maxillary im- 

 movably united to the skull.. XLIl, Derichthyid.e, 343. 

 RR. Body eel-shaped, ending in a long filament, longer than rest of 

 body. 



X. No anal or caudal fin CCXVIII, StylephoridyE, 2601. 



XX. No caudal fin; anal present CCIV, Ptilichthyid^, 2451. 



RRR. Body not truly eel- shaped. 



S. Gill openings far behind pectoral fins; mouth oblique, very 

 large; spinous dorsal represented by fleshy tentacles. 



CCXXIII, Ceratiid.e, 2727. 

 SS. Gill openings before pectoral fins. 

 T. Gill membranes broadly united to the isthmus, restricting the 



gill openings to the sides. 

 U. Snout tubular, bearing the short, toothless mouth at the end; 



body mailed CIII, Syngnathid.e, 760. 



UU. Snout not tubular. 

 V. Breast without sucking disk. 



W. Dorsal fin single, of spines or undivided rays only. 

 X. Jaws and vomer with coarse molar teeth. 



ecu, AXARHICHADIIXE, 2445. 



XX. Jaws and vomer without molars. 

 Y. Mouth nearly vertical; dorsal spines slender, rather high. 



CCI, Cryptacanthodid.e, 2442. 

 YY. Mouth not nearly vertical; dorsal spines moderate or low, some 



or all of them usually pungent CC, Bi.enxiid.e, 2344. 



WW. Dorsal fins 2, the anterior of spines, the posterior of soft rays; 

 body short and deep. 

 Z. Spinous dorsal of 2 or 3 spines; scales rather large, rough or 



bony CLXIX, Balistid.e, 1698. 



ZZ. Spinous dorsal of 1 or 2 spines; scales minute, rough, forming 



a velvety covering CLXX, MoxaCanthib.e, 1712. 



WWW. Dorsal fin continuous, of soft rays only. 



a. Body oblong or elongate, the back not elevated; dorsal and anal 

 joined to caudal. 



