Explanation" oi- Plate 3 



Fig. 1. — Dendronotus jrotidosus (Ascanius), washed ashore in September 1949. 



Figs. 2-5. — Molleria costulata (MoUer): 2, from 741 feet, showing a form with many fine- 

 ribs interrupted by a prominent carina that outlines the umbilicus; 3, 4, from 453 and 

 477 feet, respectively, forms in which the axial sculpture consists almost entirely ot 

 incremental lines but with widely spaced evanescent axial riblets posterior to the carina 

 outlining the umbilicus; shallow depressions between the riblets; 5, from 453 feet, show- 

 ing a form with fewer and much coarser ribs than in 2; ribs uninterrupted because of 

 no carina outlining the umbilicus. 



Fig. 6. — Triphora perversa (Linnaeus) from 341 feet, an immature specimen. 



Fig. 7. — Margarites frigidus Dall from 420 feet. 



Figs. 8, 9. — Margarites avenosooki, new species, from 341 feet: 8, umbilical view, showing 

 rounded shoulder and steplike cords on the base; 9, apical view. 



Magnification: 1, X .86; 2-5 X 16.7; 6, X 18.6; 7. X 6.5; 8, 9, X 13.6. 



