98 



THE NAUTILUS. 



wholly dextral, others again are either dextral aud sinistral. They 

 all possess fine spiral strife, which are decussated by oblique ones 

 giving the surface a waved appearance. 



8. Decussatula Group. 



P. decussatula Pfr. P. magdalina Hartm. 



P. bellata Hartm. 



p. decussatula. 



9. Turgida Group. 



p. arguta. 



P. rosea. 



P. ganytnedes. 



P. turgida Pfr. 

 P. annectens Pse. 



10. Rosea Group. 



P. rosea Brod. 



P. varia Brod. 



P. virgulata Migh. 



P. nexvcomhiana Hartm. 



P. argtita Pse. 

 P. minuta. Pfr. 



P. calypso O. Semp. 



P. assimilis Pse. 



P. subgonocheila Mouss. 



11. Ganymedes Group. 



P. ganymedes Pfr. 

 P. inflata Rve. 

 P. actor Albers. 



P. gonocheila Pfr. 

 P. repanda Pfr. 



II. BuLiMiNOiD Division. 

 12. Guamensis Group. 



P. gitamensis Pfr. 

 P. abbreviata Mouss. 

 P. conica Gld. 



P. o6esa Pse. 

 P. rw/a Less. 

 P. bulhnoides Less. 



p. guamensis. 



