Explanation of Plates 



Plate I 



Drawings by Clara A. Fraser. 



Fig. 1. Monohrachium parasitum 



A. Complete colony 



B. Single zooid x 40 



C. Medusa buds. 



Fig. 2. Obelia duhia. 



A. Colony, natural size. 



B. and C. Portion of branches showing arrangement of hyrod- 



thecae. 



Fig. 3. Lictorella cervicornis. 



A. Portion of colony, natural size. 



B. Simple portion of branch. 



C. Coppinia mass (After Nutting) 



