1882 Bulletin 47, United States National Museum. 



aa'. Gill membranes united, not forming a distinct fold across isthmus 

 (unless the skin is shrivelled) ; naked skin thin and lax. 



CALYCILEPIDOTUS, 726. 

 yy. Body without scales, but with a band of coarse bony plates along 



lateral line; gill membranes broadly united to the isthmus. 

 &'. Preopercular spine simple, very long and strong. ENOPHRYS, 727. 

 &&'. Preopercular spine extremely long, armed above with recurved 

 hooks. CERATOCOTTUS, 728. 



lih. Body not definitely scaly above, the skin smooth, prickly, villous, or with scat- 

 tered scaly processes; no bony armature to lateral line. 

 COTTIN.E : 



c'. Skin smooth or warty or velvety, not evenly hispid with stiff prickles. 

 e'. Gill membranes broadly united to the isthmus, not forming a fold 

 across it; fresh- water species with the head feebly armed; pala- 

 tine teeth present or absent. 



/'. Ventrals with a concealed spine and 4 soft rays ; skin often prickly. 



COTTUS, 729. 



fp. Ventrals with a concealed spine and 3 soft rays ; skin not prickly ; 

 palatine teeth usually obsolete. URANIDEA, 730. 



ee'. Gill openings narrowly joined to the isthmus, without fold. 



[LEPTOCOTTUS, 743.] 

 eee'. Gill membranes free from the isthmus or else forming a broad fold 



across it. 



g'. Palatine teeth none. 



h'. First dorsal spine not especially elevated. 



i 1 . Preopercle with 3 spines only, the upper straight, the third 

 turned downward ; skeleton well ossified ; lateral line devel- 

 oped, with or without concealed plates. 



j 1 . Lower jaw shorter than upper; suprascapula with a single 

 spine. MYOXOCEPHALUS, 731. 



jj 1 . Lower jaw longer than upper; suprascapula with a double 

 spine, the upper branch shorter. MEGALOCOTTUS, 732. 



ii 1 . Preopercle with 4 spines, the lowermost or fourth turned down- 

 ward; bones of head more or less cavernous; lateral line 

 often modified or reduced to scattered pores. 



k'. Upper preopercular spine curved or hooked upward or else 

 obsolete and hidden in the skin; skin smooth; occipital 

 ridges little developed. 



I 1 . Nasal spines obsolete; bones of head soft and spongy; lower 

 jaw projecting; lateral line reduced to scattered pores; 

 deep water sculpins allied to Psychrolutes. 

 m'. Vomer with teeth ; palatines with none. 

 n'. Preopercular spines distinct, uppermost long, sharp. 

 o'. Dorsals well separated. ZESTICELUS, 733. 



oo'. Dorsals contiguous. DASYCOTTUS, 734. 



nn 1 . Preopercular spines very short, hidden in the skin ; 

 dorsal fin continuous. COTTUNCULUS, 735. 



mm 1 . Vomer and palatines toothless. MALACOCOTTUS, 736. 

 IV. Nasal spines strong; bones of head firm; lower jaw included. 

 p 1 . Ventral fins very long, reaching- past front of anal. 



ARGYROCOTTUS, 737. 

 pp'. Ventral fins moderate, not reaching vent. 



POROCOTTUS, 738. 

 kk'. Upper preopercular spine straight; lateral line chain-like; 



joiner with teeth, an evident slit behind last gill. 

 q'. Top of head with ridges or crests; marine species. 



ONCOCOTTUS, 739. 



