138 ON A TAPEWORM PARASITIC IN THE STICKLEBACK, 
1909, Bd. xlix.), in which he records a cyst of I. agonis from the 
mandible of Bythotrephes; Fuhrmann also records from Planaria 
lactea a plerocercoid which he regards as that of a species of 
Ichthyotenia. These cases further strengthen the assumption 
that an intermediate host is necessary for the development of all 
species of [chthyotema. | 
