HYODONTIDJ3. CVI. 263 



3. A. nigripinnis, Gill. BLACK FIN. Head 44^ in 

 length; depth the same; eye 4 in head; body compressed; 

 fins blackish, darker than in the others; D. 12; A. 12; 

 lat. 1. 80; length 16 to 18 inches; a much larger fish 

 than the preceding or the next. Lake Michigan, in deep 

 water. 



4. A. hoyi, Gill. Sisco OF LAKE MICHIGAN. Head 4 

 in length; depth 4^; eye large, 3f in head; maxillary 

 2f; mandible 2; longest ray of dorsal four times the 

 length of the shortest; upper jaw somewhat projecting, 

 the mouth appearing much as in Coregonus bluish 

 above, sides lustrous silvery, more brilliant than in any 

 other species; D. 11; A. 12; lat. 1. 74; length 8 inches. 

 Smallest and handsomest of the Siscoes, in the deep 

 waters of the Upper Lakes. 



** Body elevated ; depth about 3 in length. 



5. A. tu//ibee, (Rich.) Ag. TULLIBEE. Head 4| in 

 length; D. 15; A. 15; lat. 1. 77. L. Superior and N. 



5. COREGONUS, Linnaeus. WHITE FISHES. 

 1. C. a/bus, LeSueur. LAKE WHITE FISH. Depth 

 3J in length; head small, 5^; eye 4 in head, about as 

 long as snout; form varying much with age, sex and 

 food; pale olive above; sides white; D. 13; A. 13; lat. 

 1. 75 to 86. Great Lakes and bodies of water tributary 

 to them, north to the Arctic Sea. (Various other species 

 have been described within our limits, but it is impossible 

 to distinguish them.) 



FAMILY CVI. HYODONTID^E. 



(The Moon Eyes) 



Body much compressed, covered with large, silvery 

 cycloid scales; head naked; margin of upper jaw formed 

 by intermaxillaries mesially and by maxillaries laterally; 



