202 FISHES. 



III. With two or more free spines in place of first dorsal ; yentrals 



sub-abdominal, of a stout spine and a small ray; small fishes 

 scaleless or with bony plates. . Hemibrajstchii, page 209. 



IV. Dorsal fins two, distinct, small, the first of 4 to 7 spines ; ven- 



trals abdominal; teeth feeble or wanting; scales cycloid, 

 silvery. ...... Percesoces, page 208. 



V. With the first rays of the dorsal, or the whole first dorsal, of 



simple — usually stiff spines; first ray of ventral usually 

 inarticulate (spinous dorsal forming a hump in Gydoptems ; 

 a lamellated sucking disk in Echeneis, etc., wanting altogether 

 in Aspidophoroides and GoMesox). AcAJSfTHOPTERi, page 203. 



VI. Fin rays soft and articulated (excepting occasionally one or 



two in dorsal or anal) ; no ventral spines ; scales when pres- 

 ent, usually cycloid. 

 * Ventral s jugular; dorsal and anal long, often divided. 



Ajstacanthini, page 208. 

 ** Ventrals abdominal. 



f Mouth entirely toothless ; abdomen not serrated ; lower 



pharyngeals falciform, tooth-bearing; no adipose fin; 



head naked ; fresh water. . Eventognathi, page 211. 



f f Body elongated, scaly ; a series of keeled scales along sides 

 of abdomen ; lower pharyngeals united (as in Labridm) ; 

 no air duct ; no adipose fin ; no ventral serratures ; one 

 or both jaws or else pectoral fins greatly elongated; 

 chiefly marine. , . Synentognathi, page 209. 



fff Head more or less scaly (naked in Amblyopsis, the Cave 

 Blind Fish) ; both jaws fully provided with teeth ; lower 

 jaw usually longest; dorsal far back, nearly opposite 

 anal ; no adipose fin, ventral serratures, nor peculiar 

 scales ; chiefly fresh water. . Haplomi, page 209. 



ffff Soft -rayed fishes showing none of the above combina- 

 tions of characters ; head naked ; adipose fin or abdominal 

 serratures often present ; dentition and habitat various. 



IsospoNDYLi, page 210. 

 *** Ventrals entirely wanting. 



X Jaws with teeth ; vent at the throat ; body oblong ; cave 



fishes. ..... Haplomi, page 209. 



:}::}: Jaws toothless ; vent normal; body serpentiform. 



Anacanthlni, page 308. 



