SALMONIDA, — XXXIV. 77 
aa. Jaws with distinct teeth ; scales smaller. 
6. Dorsal very long and Bi of about 20 ics scales medium ; tongue 
toothless, . . . 4 THYMALLUS, 81. 
6b. Dorsal moderate, its a 9 ti 15; fonead with teeth; teeth strong; A. 
short, of 9 to 11 developed rays. 
c. Vomer flat, its toothed surface plane, the teeth on its shaft in one or 
two rows, sometimes deciduous ; eee black-spotted, with con- 
spicuous scales. . . . « + * » » Saboto, 8. 
ce. Vomer boat-shaped, the shaft nine depressed, without teeth ; 
scales very small, more or less imbedded; species with red or gray 
spots. 2. . + + 6 6 © « «© «© © + « + SALVELINUS, 83. 
80. COREGONUS (Artedi) Linneus. WHITE-FISHES. 
(This genus contains about forty species, lake-fishes of northern 
regions, usually spawning in shallow waters or in brooks in late 
fall or winter. All are excellent food-fishes, and all are very varia- 
ble.) (The old name, of uncertain origin.) 
a. Lower jaw included ; premaxillaries broad, placed more or less vertically, 
or the lower edge turned inward ; the cleft of the mouth less than one- 
third the head. 
&. Gill rakers short, thickish, about X +16; preorbital broad, wider than 
pupil; maxillary short, broad, not reaching to eye; the supplemental 
bone narrowly elliptical; supraorbital broad; mouth very small. 
(Prosopium Milner.) 
182, C. quadrilateralis Richardson. Rounp-FisH. Puitot- 
FISH. SHAD-WAITER. MxrNOMONEE WuiTs-FisH. Body sub- 
terete, the back broad; maxillary 54 in head ; head long, the snout 
compressed and bluntly pointed ; preorbital wider than pupil. 
Dark bluish, sides paler. Head 5; depth 43. D. 11. A. 10. 
Scales 9-85-8. N.H. to L. Superior, Alaska, and N. Through- 
out the Rocky Mountains is found a closely related species, C. wil- 
liamsoni Girard, with shorter snout and longer maxillary. (Lat., 
4-sided). 
6b, Gill rakers numerous, long and slender, X + 20 to 25; preorbital long 
and narrow; maxillary rather long, the supplemental bone ovate. 
(Coregonus.) 
c. Tongue toothless; body robust, elevated at the shoulders in the adult; 
the head very small, especially in old examples. 
183. C. clupeiformis (Mitchill). Common Watrts-risu. 
Snout bluntish, obliquely truncate; preorbital not half pupil; max- 
illary past front of orbit, 4 in head; eye large; gill rakers 2 eye. 
Color pale, scarcely silvery. Head 5 to 6; depth 2} to4. D. 11. 
A.11. Scales 8-74-9. L. 30. Great Lakes and N.; by far the 
most valuable of the American white fishes. Very variable; feeds 
on minute organisms. (Clupea, herring ; forma, shape.) 
cc. Tongue with about 3 series of small teeth; body rather elongate; the 
back scarcely elevated. 
