314 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



14. Argyrosomus laurettsc (Bean). 



Lauretta Whitkfish. 



Coregontts laurettce Beau, Proc. U. S. Nat. Mus. 1881, 156, Point Barrow. (Types 

 Nos. 27695 and 27915.) 



Head, 5 5 depth, 4; eye, 4% to 5. 1). 12; A. 11; V. 12; scales, 10-84 

 to 95-10, 84 to 87 in specimens examined by us. Body robust, the back 

 elevated; head small and slender, the small eye not longer than snout. 

 Distance from nape to front of snont 2£ times distance of nape from 

 dorsal. Maxillary about reaching' middle of eye, 3£ in head, its sup- 

 plemental bone half its length. Lower jaw very slightly longer than 

 upper; mandible, 2£ in head; lingual teeth present. G-illrakers long 

 and numerous, 10+25; ventral scale not half length of fin; pectorals 

 short, not reaching half way to ventrals. Scales smaller than in A. 

 artedi, 16 cross series under base of dorsal. Alaska, from Yukon 

 River northward to Point Barrow; generally common. Apparently 

 very close to A. luddus, but differing in longer base of dorsal. 



15. Argyrosomus prognathic (H. M. Smith). 

 Bloat; Bloater; Bloater Whitefish; Longjaw; Silver Whitefish, 



Corer/onus prognathus Hugh M. Smith, Bull. IT. S. FishCoinm., xiv, 1894, 4, pi. 1, fig. 

 3, Lake Ontario, at Wilson, New York. (Type, No. 45568.) 



Description: Head, 4^; depth, 3 A to 4; eye, 5. D. 9 or 10; A. 10 to 12. 

 Eye rather small; 1£ hi snout, li in interorbital space. Scales, 9-75-8. 

 Body oblong, much compressed; back elevated, tapering rather sharply 

 toward the narrow caudal peduncle, the adult fish having a slight 

 nuchal hump, as in G. clupeiformis. Mouth large and strong; snout 

 straight, its tip on level with lower edge of pupil. Top of head 24 in 

 distance from occiput to front of dorsal. Maxillary reaching to opposite 

 pupil, 2i in head; length, 3 1 times its greatest width; mandible pro- 

 jecting beyond upper jaw when mouth is closed, very long, reaching to 

 or beyond posterior edge of eye, If to lg in head. Head of medium 

 size, rather short and deep, pointed; cranial ridges prominent. 



Dorsal rather high, the longest ray one-third longer than base of fin 

 and contained 1§ times in greatest body depth and \\ times in head; 

 free margin slightly concave; origin nearer end of snout than base of 

 caudal. Longest anal ray equal to base of fin or two-thirds height of 

 dorsal. Vertebra', 55. Gillrakers slender, about 15 + 28, about length 

 of eye. Adipose fin the length of eye, its width half its length. Nar- 

 rowest part of caudal peduncle contained nearly 4 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 



