290 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. VII. 



Genus Coregoiius (Artedi) Linnaeus. 

 THE WHITEFISHES. 



Body more or less elongate, moderately compressed; head small, 

 conical, the blunt snout formed by the broad premaxillary ; premax- 

 illary with cutting edge nearly vertical; lower jaw the shorter; jaws 

 toothless or nearly so ; gill rakers usually short ; caudal deeply forked ; 

 pyloric cceca about 100; air bladder large. 



a. Body compressed, the dorsal region much elevated; gill rakers 

 17 to 20 on lower limb of first gill arch; head short, 5 to 5.3 in 

 body. albus, 290 



aa. Body long, slender, the dorsal region little elevated; gill rakers 

 ii or 12 on lower limb of first arch; head longer, 3.7 to 4.3 in 

 body. quadrilateralis, 291 



Coregonus albus Le Sueur. COMMON WHITEFISH. 

 Head 5 to 5.3; depth 3 to 4; D. 11 ; A. 10; scales 74. 

 Body oblong, compressed, the back elevated; head very small; 



FIG 51. COMMON WHITEFISH. 



Coregonus albus Le Sueur. (After Evermann and Smith.) 



interorbital space 3.4 in head; diameter of eye 4 to 5 ; snout 3.8 ; max- 

 illary reaching past front of orbit ; its length about 4 in head ; lower 

 jaw the shorter; lateral line complete. 



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

 times dusky. 



Great Lakes and neighboring waters. 



Lake Michigan, Chicago, Illinois; Lake Michigan, Pine and Mil- 

 lers, Indiana. 



