PLATE I 



Figure 1. Entalis striolata. 



2. Acmxa testudinalis. 



(A), showing head, branchia, branchial arteries, mantle, 

 papillae. 



(B), tentacle greatly enlarged, 



(C), mouth showing radula within. 



3. Acmsea alveus. 



(A), head thrown to one side. 



(B), enlarged view of head with tentacles and mouth 

 from below. 



