Explanation of Plate 1 



Fig. 1. — Margarites costalis var. grandis Morch from 341 feet, showing flattened base and 

 almost complete absence of basal lirae. 



Figs. 2, 3. — Varieties of Margarites costalis (Gould) from 341 feet, showing flattened base: 

 2, with weak basal lirae, central ones very faint; 3, with strong basal lirae throughout. 



Figs. 4-7. — Varieties of Margarites costalis (Gould): 4, from 453 feet, with somewhat rounded 

 base and weak basal lirae; 5, forma multilirata ^ Odhner from 341 feet, with strongly 

 rounded base and very faint basal lirae; 6, from 341 feet, with somewhat rounded base 

 and strong basal lirae; 7, shown with its operculum, from 741 feet, base strongly 

 rounded, strong basal lirae, and a few faint intercalary threads between primary lirae 

 of body whorl. 



Fig. 8. — Margarites avenosooki, new species. Paratype (Stanford Univ. Paleo. Type Coll. 

 No. 8331) from 420 feet, showing flared umbilical opening. 



Fig. 9. — Solariella ohscura (Couthouy) from 132 feet, apical view. 



Fig. 10. — Natica clausa Broderip and Sowerby from 420 feet (shown with its operculum). 



Fig. 11. — Crepidula grandis Middendorff from 130 feet (Sept. 15, 1948), showing strongly 

 curved apex and heavy periostracum. 



Magnification: All X 17.7. 



