98 



THE NAUTILUS. 



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

 all possess fine spiral stria;, "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. ganymedes. 



P. turgida Pfr. 

 P. annectens Pse. 



10. Rosea Group. 



P. rosea Brod. 



P. varia Brod. 



P. virgidata Migh. 



P. newcomhiana Hartm. 



P. arguta Pse. 

 P. minuta Pfr. 



P. calypso 0. Semp. 



P. assimilis Pse. 



P. subaonocheila Mouss. 



11. Ganymedes Group. 



P. ganymedes Pfr. 

 P. inflata Rve. 

 P. actor Albers. 



P. gonocheila Pfr. 

 P. repanda Pfr. 



n. BuLiMiNOiD Division. 

 12. Guamensis Group. 



P. guamensis Pfr. 

 P. abbreviata Mouss. 

 P. conica Gld. 



P. obesa Pse. 

 P. ruja Less. 

 P. bulimoides Less. 



p. guamensis. 



