Bull. U. S B. F. 1912. 



Plate XCIII. 



I-iG- ^S. — Wild Wisconsin brook trout. Ked marine fish 13 months. Nonnal thyroid, Xsf. 





aic'TS - *'>*Si ^f- "^.--t , • 



tT-r*.! 





Fitj,. by. — wild Wisconsin brook trout. VcKetable J'ootl 12 months. Normal thyroid. XS6. 



