Bull. U. S. F. C. 1891. Fish-cultural Investigations in Montana and Wyoming. (To face page 60 — 16.) 
Plate XXI 
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■ -• . ?' ■ : 
1. COREGONUS WILLIAMSoni Gird. Williamson’s Whitefisk. Adult. One-half natural size. 
2. COREGONUS WILLIAMSON). Young. 
3. CoREGONUS WILLIAMSONI. Head of breeding male. Natural size. 
