218 FISHES. 



h. No teeth on vomer or palatines ; mouth small, contracted, 

 subinf erior ; head short and thick, with swollen cheeks ; 

 spinous dorsal rather long; maxillary non-protractile; 

 anal spmes strong ; body elongated, little compressed. 



DiPLESIUM, 9. 



hh. Vomerine teeth present ; dorsals contiguous, but distinct ; 

 the spinous dorsal short; max. protractile ; the mouth 

 rather small, horizontal, subinferior. 



i. Anal spines two, well developed; the first the longer. 



Ulocentra, 10. 



ii. Anal spines obscure and undift'erentiated from the soft 



rays Boleosoma, 11. 



gg. Upper jaw not protractile. 



j. Gill membranes broadly connected across breast ; 

 scales large; cheeks and opercles scaly; mouth small, 

 horizontal, subinferior (as in Boleosoma) ; caudal pe- 

 duncle rather slender. . . . Nanostoma, 12. 



jj. Gill membranes nearly free ; body rather shorty 

 deep, strongly compressed ; scales small ; cheeks naked ; 

 mouth rather large, oblique (as in PcBcilichthys) ; caudal 

 peduncle deep Nothonotus, 13. 



''** Lateral line incomplete or wanting; no ventral plates; upper 

 jaw not protractile ; second dorsal larger than anal ; vomer 

 with teeth. 

 Jc. Lateral line present on anterior part of body; anal spines 

 two. 



I. Lateral line nearly straight. 



m. Spinous dorsal fin well developed, two-thirds or more 

 the height of the second ; the spines graduated, never 

 ending in little fleshy knobs; lateral line extending 

 more than half the length of the body ; mouth moder- 

 ate, the upper jaw usually a little the longer; gill 

 membranes free. . . . Pcecilichthys, 14. 



mm. Spinous dorsal low and small, the spines subequal, 

 scarcely half the height of the soft rays, in males end- 

 ing in little fleshy knobs; gill membranes connected ; 

 body elongated, compressed. . Etheostoma, 15. 



