PLATE IV. 



FIG. i. Amfhfyorus nebulosussynov. Kukak Bay, Alaska Peninsula. Natural 

 size. 



2. Micrura alaskensis sp. nov. Sitka. Enlarged i^ times. 



3. Cerebratulus albifrons sp. nov. Near Sitka. Twice natural size. 



4. Side view of head of same individual. 



5. Amphiporus tigrinus sp. nov. Farragut Bay. Mature male specimen, 



slightly enlarged. 



6. A. tigrinus. Head of male ; dorsal view. Twice natural size. 



7. A. tigrinus, Farragut Bay. Female with ripe ova. Slightly en- 



larged. 



8. Head of female of same species. Dorsal view. Twice natural size. 



(92) 



