148 TELEOSTEI : ACANTHOPTERI. — XX. 
Arctic fishes, numerous, 35 to 50. Genera 40; species 150, mostly 
of the springs, rock-pools, and seashores of Arctic regions; a few in 
the deep sea. Singular fishes, mostly of small size, and of little 
value as food. ‘The fresh-water species are very destructive to 
egos of other fishes. 
a. Spinous D. longer than soft part, of more than 14 spines. (Hemitrip- 
tering.) 
6. Spinous D. deeply notched, the anterior spines highest; skin with prickles 
and warts; teeth on vomer and palatines; gill membranes free from 
isthmus; no slit behind last gill. . . . . HEMITRIPTERUS, 186. 
aa. Spinous D. shorter than soft part, of less than 13 spines; dorsal spines not 
concealed; gill openings not very small. V. present. ( Cottine.) 
c. Vomer with teeth. 
d. Slit behind last gill obsolete or reduced to a round pore; skin with- 
out true scales. 
Gill membranes broadly united to the isthmus, not forming a fold 
across it; head feebly armed; palatine teeth few or none. 
Cortus, 187 
ee. Gill membranes free from isthmus or else forming a broad fold 
across it; head well armed. 
J. Palatine teeth none; skin naked or prickly. 
ACANTHOCOTTUS, 188. 
Jf. Palatine teeth well developed; skin smooth. 
ARTEDIELLUS, 189. 
dd. Slit behind last gill small, but evident; no palatine teeth. 
g. Skin smooth; gill membranes not quite free from isthmus; 
preorbital, etc., strongly cavernous. . TRIGLOpsIs, 190. 
gg. Skin with minute prickly scales, and with plates along back 
and lateral line; gill membranes free from isthmus. 
TRIGLOPs, 191. 
cc. Vomer without teeth; preopercular spine antler-like; a fold across 
isthmus and no slit behind last gill; no scales. 
GYMNACANTHUS, 192. 
186. HEMITRIPTERUS Cuvier. (jmu-, half; rpeis, three; 
mrepov, fin.) 
404. H. americanus (Gmelin). SEA Raven. Head large, 
with many humps and ridges above. Brown, body and fins much 
variegated with blackish. Head 22; depth 3%. D. IV, XII, 1,12. 
A. 13. Lat.1.40. L.18. Cape Cod to Arctic Sea. 
187. COTTUS (Artedi) Linneus. (Uranidea DeKay.) MILLER’s 
Tuums. (Ancient name of C. gobio, from korros, head.) 
a. Palatines with teeth; ventrals I, 4 (the spine obscure). 
6. Preopercular spine large, as long as eye, strongly hooked upward; skin 
above with coarse prickles (Tawridea Jordan & Rice). 
405. C. ricei Nelson. Head broad, body contracted at base of 
tail. Olivaceous, finely speckled. Head 33; depth5}. D. VIII-17. 
A.12. L. 2%. Lake Mich. and L. Ontario, rare. (To Frank L. 
Rice.) 
