Bull. U. S. B. F. 1912. 



Plate LXV. 



Fig. 25. — Jlrook trout, showing rectal nietastnsis of thyroitl origin (Anal fin pinned back to sliow tumor.) 



Fig. 24. — Brook trout, showing large 

 round tumor springinK from the jugular pit. 



Fig. 23a. — A view of nonnal floor of 

 mouth of a<lult brook trout. 



Fig. 23 — Hyperemia of floor of mouth of adult brook trout, 

 so-called red floor. First macrcscopic evidence of hyperplasia or 

 carcinoma of thyroid. 



