218 FISHES. 



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

 subinferior ; head short and thick, with swollen cheeks ; 

 spinous dorsal rather long ; cheeks and opercles scaly ; 

 anal spines strong; body elongated, little compressed. 



DIPLESIUM, 9. 



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

 the spinous dorsal short ; head narrowed ; the mouth 

 rather small, horizontal, subinferior. 

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



ULOCENTRA, 10. 

 ii. Anal spines obscure and undifferentiated from the soft 



rays BOLEOSOMA, 11. 



gg. Upper jaw not protractile. 



j. Dorsal fins well apart ; body fusiform, little compressed ; 

 scales large ; cheeks and opercles scaly ; mouth small, 

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

 duncle rather slender. . . . NANOSTOMA, 12. 

 jj. Dorsal fins slightly connected at base ; body rather short, 

 deep, strongly compressed ; scales small ; cheeks naked ; 

 mouth rather large, oblique (as in PwcilicJithys) ; 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. 



k. Lateral line present on anterior part of body. 

 I. Dorsal fins contiguous, the membrane of the first reaching 



to the base of the second. 



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; opercles 

 scaly ; cheeks naked ; body rather short and deep. 



POSCILICHTHYS, 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 ; mouth rather large ; body 

 elongated, compressed. . . ETHEOSTOMA, 15. 



