202 PISHES. 



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

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

 scaleless or with bony plates. . HEMIBRANCHII, 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 Oyclopterus ; 

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

 in Aspidoplwroides and Gobiesox). ACANTIIOPTERI, 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. 

 * Ventrals 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 Ldbrida} ; 

 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. 



f fff 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. 



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

 fishes. . . . . . HAPLOMI, page 209. 



\\ Jaws toothless ; vent normal ; body serpentiform. 



ANACANTHINI, page 208. 



