472 Bulletin 47, United States National Museum. 



beyond posterior edge of eye, If to !$ in head. Head of medium size, rather 

 short and deep, pointed, cranial ridges prominent. Dorsal rather 

 high, the longest ray i longer than base of fin, contained If times 

 in greatest body depth, and !- times in head; free margin slightly con- 

 cave ; origin nearer end of snout than base of caudal. Longest anal 

 ray equal to base of fin and height of dorsal. Vertebrae 55. Gill 

 rakers slender, about 15 -f- 28, about length of eye. Adipose fin the 

 length of eye, its width half its length. Narrowest part of caudal pedun- 

 cle contained nearly four times in greatest body depth. Ventral as long 

 as dorsal is high, its origin midway between end of snout and' fork of 

 tail; pectoral as long as ventral. Lateral line straight except at origin, 

 where it presents a rather marked curve. Sides of body uniformly 

 bright silvery, with pronounced bluish reflection in life ; the back dusky, 

 the under parts pure white without silvery color ; above lateral line, the 

 upper and lower edges of scales are finely punctulated, central part 

 unmarked, producing light longitudinal stripes extending whole lengfch 

 of body ; fins flesh color or pinkish in life, the dorsal and caudal usually 

 showing dusky edges ; postorbital area with a bright golden reflection. 

 Iris golden, pupil black. Length 15 inches. Lake Ontario, Lake Michi- 

 gan, Lake Superior, and doubtless the entire Great Lake Basin, in deep 

 water. (Smith.) This species and A. osmeriformis have been confounded 

 under the name Coregonus hoyi, though neither much resembles the 

 original of that name. (?rp6, forward ; yvaOoc, jaw.) 



Argyrosovms hoyi, MILKER, Kept. U. S. Fish Comm., n, 1872-73 (1874), 86, Outef Island, 



Lake Superior; (Coll. Milner); not of GILL. 

 Coregomts prognathus, HUGH M. SMITH, Bull. U. S. Fish Comm., xiv, 1894, 4, pi. 1, fig. 3, Lake 



Ontario, at Wilson, New York. (Type, No. 45568. Coll. John S. Wilson.) 



770. ARGYROSOMUS NIGRIPINNIS, Gill. 

 (BLUEFIN ; BLACKFIN.) 



Head 4 ; depth 4 ; eye 4| . D. 12 ; A. 12 ; scales 9 or 10-73 to 77-7 or 8. 

 Vertebrae 57. Gill rakers about 18 + 30, rather long and slender, 1 

 in eye or 2 in maxillary. Lower jaw slightly projecting; the maxillary 

 greater than eye and reaching vertical of front of pupil. Body stout, 

 fusiform, compressed. Head large, stout ; mouth large. Distance from 

 tip of snout to occiput about 3i in distance from snout to origin of dorsal 

 fin. Back not arched, profile from occiput to origin of dorsal very gently 

 curved. Eye rather large, longer than snout. Teeth very minute, but 

 appreciable on premaxillaries and tongue. Color dark bluish above ; 

 sides silvery, with dark punctulations ; fins all blue-black. Length 18 

 inches. Deep waters of Lake Michigan and small lakes of Wisconsin 

 and Minnesota (Madison, Wisconsin, and Lake Miltona, Minnesota); 

 locally abundant. Larger than most of the other Ciscoes, and with 

 larger mouth than any except A. prognathus; known at once by the 

 black fins, (niger, black; piwna, fin.) 

 Argyrosomus nignpinnis, GILL MS. in MILNER, Report U. S. Fish Comm. for 1872-73 (1874), 87 t 



Lake Michigan, off Racine, Wisconsin. (Coll. Dr. Hoy.) 

 Coregonus nigripmnis, JOEDAN, Man. Vert., Ed. 2, 275, 1878 ; JOBDAN & GILBERT, Synopsis, 301, 1883 



