PLATE VI. 



FIG. i. Cerebratulus montgomeryi sp. nov. Dutch Harbor, Unalaska. Natural 

 size. 



2. Head of same species from ventral surface. 



3. Cerebratulus occidentalis sp. nov. Yakutat. Natural size. 



4. Ampkiporus angulatus (Fabr.) Verrill. Kadiak. Natural size of large 

 specimen. 



