196 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 6 



EXPLANATION OF PLATE 21 



Figs. 



1. Virgulina seminuda Natland. xl30. 



2, 3. Bolivina acerosa Cushman, var. pacifica Cushman and Mc- 

 Culloch, new variety, x 130. 2. Holotype, a, front view; b, 

 apertural view. 3. Paratype. 



4-6. Bolivina advena Cushman. x 90. a, front view; b, apertural 

 view. 



7-11. Bolivina advena Cushman, var. striatella Cushman. x 120. 

 a, front view; b, apertural view. 



12. Bolivina aenariensis (Costa) (?) x 130. 



13-15. Bolivina albatross't Cushman. x 120. a, front view; b, aper- 

 tural view. 



