Jordan and Everma nn . — Fishes of North A mey ica . 1883 



qq'. Top of head unarmcd.or nearly so; lacustrine species. 



Triglopsis, 740. 

 kkV. Upper preopercular spine stont, armed with 2 or 3 antler- 

 like processes ; slit behind last gill small or wanting ; 

 vomer toothless. Gymnocanthus, 741. 



M'. First dorsal spine elevated : skin perfectly smooth ; gill mem- 

 branes forming a broad fold across isthmns. Leiocottus, 742. 

 gg<. Palatine teeth present (rarely obsolete in one species). 



»•'. Gill membranes narrowly joined to the isthmus, not forming a 

 fold; preopercular spine with antler-like processes; skin 

 smooth. Leptocottus, 743. 



rr'. Gill membranes free from the isthmus; preopercular spine shorter ; 

 liead and sides usually with many short cirri. 

 s'. Skin of sides with scattered prickles or rudimentary scales; 

 preopercular spine bifid ; bead pointed. Clinocottus, 744. 

 *■«'. Skin perfectly smooth, without scales or prickles. 

 v. Preopercular spine long and sharp, sometimes with 1 antler- 

 like process above; snout acute. Oligocottus, 745. 

 tV. Preopercular spine sharp, curved, simple; snout acute. 



OXTCOTTUS, 746. 

 UV. Preopercular spine short and blunt: snout more or less obtuse. 



Blenxicottus, 747. 



rrr' . Gill membranes free from the isthmus; no cirri; preopercular 



spine slender, hooked upward. [ Artediellus, 714.] 



BLEPSIIN^ : 



cc'. Skin almost everywhere rough with small bluntish prickles; first dorsal, 

 elevated in front; head small, compressed. 

 u'. Gill membranes free from the isthmus ; ventrals .small. 

 V'. Spinous dorsal not emarginate ; no .smooth areas on body. 



HisTiocoTxrs, 748. 

 vv' . Spinous dorsal deeply notched ; sides with smooth areas. Blepsias,749. 

 uu'. Gill membranes united to the isthmus ; ventrals long. 



w'. First dorsal little elevated, its base scarcely raised above occiput. 



Nautiscus, 750. 



WW'. First dorsal greatly elevated, its base raised abruptly from the 



depressed occiput. Xautichthys,751. 



HEMITRIPTERIN.E : 



ijij. Spinous dorsal longer than soft part, of 14 to 18 spines; skin rough, with prickles 



and tubercles ; teeth on vomer and palatines ; gill membranes free from isthmus ; 



no .slit behind last gill. 



%'. Spinous dorsal of lu spines, not notched. Ulca, 752. 



XX'. Spinous dorsal of 16 to 18 spines, deeply notched, the anterior spines highest. 



Hejiiteipteeds, 753. 



SyXCHIEINJE: 

 hh. Pectoral fins continuous around the throat. 



J/'. Back with spinous scales; giU membranes free from isthmus; no slit 

 behind last gill; teeth on vomer and palatines; preopercle with a 

 short bifid spine ; ventrals inserted far back. Stnchirds, 754. 



ASCELICHTHYIX^ : 



aa. Ventral fins wholly wanting. Skin perfectly smooth ; no slit behind fourth giU; 

 gill membranes free from isthmus ; teeth on vomer and palatines. 



ASCELICHTHYS, 755. 

 PSYCHEOLUTIN.E : 



rr. Spinous dorsal not evident, its slender spines wholly hidden in the skin or else indis- 

 tinguishable from soft rays; head unarmed, its bones hidden in lax skin; akin 

 smooth; no slit behind last gill; gill membranes broadlj- joined to the isthmus; 

 no tectli on vomer or palatines ; maxillary covered by skin of preorbital; ventrals 

 moderate I, 3, the base adnata to body. 



