Jordan and Evennan^i. — Fishes of North America. 1911 



717. ICELUS, KriJyer. 



Icelus, Kroyer, Naturalist Tiilaskr. i, 253, 1845 (hamatus) . 



Head large. Preopercular spines 4, the upper hooked, simple or bifur- 

 cate at tip, without antler-like processes. Occiput wi th or without spines. 

 Body slender, fusiform, with a dorsal series of bony plates from neck to 

 base of caudal; lateral line with osseus tubercles; scattered scales on 

 sides and belly. Gill membranes broadly united, free from the isthmus, 

 no slit behind fourth gill. Dorsals separate; ventrals I, 3, thoracic; no 

 pectoral lilameuts. Villiform teeth on jaws, vomer, and palatines. 

 Brauchiostegals 6. Arctic regions. ("IkeAoj, Icelus, son of Hypnus, the 

 god of sleep; Kroyer says: "Navuet valgt med Heusyu till ulkearternes 

 Dorskhed, saavelsom til den Nordlige Bopael, nogle af Oldtidens Forfat- 

 tere anviste S^vnguden.") 



a. Aual rays 14 or 15; depth about 5 in length ; dorsal IX, 18 to 20; occiput with 2 

 pairs of spines on each side, a deep median pit between them. bicornis, 2291. 

 aa. Anal rays 17 to 19 ; dorsal VII to IX, 19 to 24 ; depth 5 to 6 in length. 



b. Dorsal with 19 or 20 soft rays; depth 5 in length; occiput nearly plain, without 

 pit or prominent ridges. spiniger, 2292. 



bb. Dorsal with 23 or 24 soft rays. 



c. Dorsal spines IX; head with the mucous channels not greatly developed ; 

 top of head scaly or prickly. 

 d. Eye 2J to 2^ in head, twice length of snout. eueyops, 2293. 



(Id. Eye 2g to 3 in head, IJ times length of snout; top of head with 3 

 paii-8 of filaments. Vicinalis, 2294. 



cc. Dorsal spines VII or VIII ; top of head mostly smooth ; opercles smooth ; 

 1 pair of filaments on top of head ; muciferous channels of head 

 highly developed. canaliculatus, 2295. 



aaa. Anal and dorsal rays unknown ; body very slender; depth 7 in length; no occipi- 

 tal spines ; eye 3 in head. AUSTBALIS, 2296. 



2-291. ICELl'S BICOR.XIS (Ueinhardt). 



Head 3 ; depth 5. D. IX, 19 or 20 ; A. 14 or 15 ; V. I, 3 ; P. 18 or 19. Head 

 large, naked; upper preopercular spine small, hooked upward, bifur- 

 cate, 3 spines below it, 2 of them hooked upward; 2 blunt occipital 

 spines; vertex depressed. Skin of body above with warty scales and 

 small prickles; some rows of bony scales from neck to base of caudal; a 

 series of plates along lateral line ; sides of body with scattered scales ; 

 scales on sides between the plates variables as also the scales below pec- 

 torals; small scales sometimes along base of anal; interocular space very 

 narrow, its width 4 in eye ; dorsals separated ; pectorals shorter than head ; 

 nuchal spines varying with age; with the young the anterior pair half- 

 way between eye and posterior pair, with adults, the 2 pairs touching, 

 the posterior much longer ; preopercular spine simply emarginate in young ; 

 adult with the plates more rough ; no air bladder ; gill membranes broadly 

 joined, free from isthmus; no slit behind last gill. Yellowish, with many 

 brown spots. 



Ensign H. G. Dresel thus describes a fine example, 6 inches long, of 

 this species (No. 28630 U. S. Nat. Mus. collection) ol>tained in Davis Straits 

 by Mr. N. P. Scudder: D. IX, 20; A. 16; P. 18; V. 1,3; lateral line 41. 



