Jordan and Evermann. Fishes of North America. 1019 



./. Ventral fins well separated, the interspace about equal to width of 



their base. 



//. Middle line of belly with more or less enlarged, caducous plates, 

 which are shed at certain seasons, leaving a naked strip. 



HADROPTERUS, 466. 



AA. Middle line of belly with small, persistent scales like those of 



sides. HYPOHOMUS, 4G7. 



ff. Premaxillaries protractile, a groove separating them from the skin of the 



forehead, rarely crossed by a narrow frenum in one species (slmmardi) . 



i. Anal spines 2, both well developed, the first usually the longer, the 



second rarely obsolete. 

 j. Maxillary normal, free from the preorbital, except at base; vomer 



usually with teeth. 



k. Anal fin rather large, scarcely smaller than second dorsal; 

 mouth not very small; belly naked or with caducous 

 plates, at least anteriorly; gill membranes scarcely con- 

 nected, ventral fins well separated. COTTOGASTER, 468. 

 kk. Anal fin short and small, much smaller than second dorsal; 

 mouth small; belly covered with ordinary scales; gill 

 membranes broadly connected across the isthmus; ven- 

 tral fins inserted close together. ULOCENTRA, 469. 

 jj. Maxillary adnate to the preorbital for most of its length, and 

 therefore nearly immovable; mouth very small, inferior; no 

 teeth on vomer; ventral fins close together. DIPLESION, 470. 

 ii. Anal spine single, obscure; dorsal spines usually 9, slender; anal fin 

 small, much shorter than soft dorsal; ventral fins well separated. 



BOLEOSOMA, 471. 



ee. Body extremely elongate, hyaline, subterete, the belly mostly naked; 

 lateral line complete; head long, pointed; gill membranes somewhat 

 united. 



/. Premaxillaries not protractile, free only at the sides; dorsal spines 14; 

 anal fin large, with 1 spine; scales very small. CRYSTALLARIA, 472. 

 U. Premaxillaries protractile; dorsal spines 7 to 11. 



in. Anal spine single; anal nearly as large as second dorsal; vertebrae 



41 to 44; bones of skeleton very thin. AMMOCRYPTA, 473. 



mm. Anal spines 2; anal fin small, much smaller than second dorsal. 



IOA, 474. 



cc. Parietal region of skull not depressed, more or less strongly convex in cross- 

 section, thus, ("I ; premaxillaries never protractile ; belly covered with ordi- 

 nary scales; veutrals inserted close together; anal fin rather small, of 7 to 9 

 soft rays, notably smaller than second dorsal, usually with 2 spines; vertebra 

 31 to 36, the bones rather firm. 



ra. Lateral line developed, at least anteriorly; dorsal spines 8 to 14. 

 o. Lateral line straight; body rather robust. 

 p. Head naked above. 



q. Dorsal fins large, usually with more than 7 spines. 



ETHEOSTOMA, 475 



qq. Dorsal fins small, VI-10. ALVARIUS, 476. 



pp. Head completely scaled above. PSYCHUOMASTER, 477. 



oo. Lateral line with a slight arch running high anteriorly; dorsals well 



separated; body slender. 



r. Head scaled above. COPELANDELLUS, 478. 



rr. Head naked above. BOLEICHTHYS, 479. 



tin. Lateral line wholly wanting; fins all very short, only 6 dorsal spines; verte- 

 bra) 14 + 16 = 30. MICROPERCA, 480. 



