Bull. U. S. B. F., 1925. (Dor. 972) 
Fig. 1. — Extensive infection of a JMnch fish. ^I'lie tumors aie still in the "young" stage, scarcely raised above the 
surface. The areas of dense black seem to indicate four centers of infection. 
Fig. 2.— "Old" tumor involving all of the adipose fin and extending downward on both sides. A slight margin of 
younger growth is seen about the base of the older, dense black portion. 
Fig. 3.— An "old" tumor involving the caudal peduncle and the base of the caudal fin, extending on both sides. The 
highest portkin of this tumor is nearly half an inch above the natural dorsal line. 
Fig. 4. — Tumors on the lips. That on the lower jaw is "older" and somewhat fimbriated on the surface. That on 
the upper jaw involves a portion of the oral surface. The left maxillary barbel shows infection in a very young 
stage. 
