4G. SALMONID/E - COEEGONUS. 299 



tt Gill-rakers numerous, long and slender ; preorbital long and narrow ; maxillnries 

 comparatively loug; the supplemental bone ovate, rather broad. (Coregonus.') 

 t Tongue toothless, or nearly so; back elevated. 



49. C. clfllsseifoa'Mias (Mitch.) Milner. Common White-fish. 



Body oblong, compressed, always more or less elevated, and becoming 

 notably so in the adult. Head comparatively small and short, the snout 

 bluntish, obliquely truncated; tip of snout on level of lower edge of 

 pupil j width of preorbital less than half that of pupil. Maxillary 

 reaching past front of orbit, about 4 in head. Eye large, 4-5 in head. 

 Gill-rakers moderate, diameter of eye, about 20 below the angle. 

 Color olivaceous above; sides white, but not silvery; lower fius some- 

 times dusky. Head 5; depth 3-4. D. 11; A. 11; scales 8-74-9. L. 20 

 inches. Great Lakes and northward; the best known and most highly 

 valued of the American white-fishes. This species, like others of wide 

 distribution, is subject to considerable variations, dependent on food, 

 waters, etc. Feeds on minute organisms. 



(Salmo dupeiformis Mitchill, Arner. Mouth. Mag. ii, 321, 1818: Coregonns albus Le 

 Sueur, Jouru. Acad. Nat. Sci. Phila. i, 231, 1818 : Coregonus albus Giiuther, vi, 184, aud 

 of authors generally: Coregonus richardsoiti Gunther, vi, 185: Coregonus sapidissimus 

 Giiuther, vi, 18G : Coregonus laiior Guuther, vi, 186 : Coregonus olsego, the " Otsego Lake 

 Bass", DeWitt Clinton Med. & Phil. Register, iii, 188.) 



tt Tongue with about three series of small teeth; body elongate, compressed. 



491, C. labradoricus Rich. " Whiting" ; Musquaiv River White fish. 



Body rather elongate, compressed, the back not elevated. Head. 

 rather long and slender, compressed. Mouth rather small, the jaws 

 equal, the maxillary reaching to the front of the pupil. Maxillary 

 bone broad, rather short, its supplementary piece ovate. Mandible 

 reaching middle of eye. Eye large, 4} in head. Supraorbital bone 

 narrow. Gill-rakers rather long. Bluish black above, silvery below; 

 scales with dark pimetulations ; fius all dusky. Dorsal fin high in 

 front, the last rays short. Head 4 ; depth 4^. D. 11; A. 11; scales 

 9_80-8. L. 12 inches. Great Lake region to the lakes of the Adi- 

 roudacks aud White Mountains, and northeastward ; generally abun- 

 dant in cold, clear lakes. 



(Richardson, Fauna Bor.-Amer. iii, 203, 1836 ; Giinther, vi, 176 : Coregonus neohan- 

 toniensis Prescott, Arner. Jouru. Sci. Arts, xi, 342, 1851.) 



ttt Tongue nearly toothless ; back not elevated. 



492. C. Iioyi (Gill) Jordan. Lake Moon-eye; Cisco of Lake Michigan. 



Body rather elongate, compressed, the back somewhat elevated. 

 Head rather long, in form intermediate between Coregonus and Argyro- 



