186 CEPOLIS. 



we are evidently near the horizon where the paths of the various 

 sections of the genus Cepolis diverged, although the better defined 

 forms of the genus no doubt have older roots. 



The species of Plagioptycha are numerous and especially charac- 

 teristic of the Bahamas, extending south to Hayti and the Virgin 

 Islands. In Miocene times they extended to the (then) island of 

 Florida, but later became extinct there, for the present Floridian 

 land shell fauna is not directly descended from that of the Miocene 

 island. Some forms of Plagioptycha approach Hemitroehus, and 

 others are near Cysticopsis, so that the grouping, as in many of these 

 sectional divisions, is somewhat arbitrary. 



Umbilicate species, the columellar lip expanded, not adnate to base 

 (Bahamas). 



C. indistincta F6r., v, 14. C. bahamensis Pfr., v, 18. 



v. disculus Dh., v, 15. v. holostoma Pils., v, 18. 



v. chromochila Pils., v, 15. C. sargenti Bid., v, 18. 



C. strumosa Pfr., v, 15. C. duclosiana Fer., v, 19. 

 C. ru'sii Pfr., v, 16. v. salvatoris Pfr., v, 19. 



C. platonis Pfr., v, 16. v. abacoensis Mts., v, 20. 



C. albersiana Pfr., v, 17. C. macroglossa Pfr., v, 20. 

 C. loxodon Pfr., v, 17. 



Imperforate species, with adnate columellar lip (Hayti to Virgin Is.). 



C. monodonta Lea, v, 21. C. diaphana Lam., v, 22. 



v. acuminata Pfr., v, 21. C. santacruzensis Pfr., v, 23. 



haitensis W. & M., v, 21. C. phsedra Pfr., v, 23. 

 C. nemoralina Pet., v, 22. justi Pfr. 



f. intensa Pils., v, 22. 



Section Cysticopsis Morch, 1852. 



Cysticopsis MORCH, Catal. Yoldi, p. 2 (proposed for cubensis Pfr. 

 only). Pilsbry, Man. Conch, v, p. 10, Cuban species. Not Cysti- 

 copsis MARTENS, Die Hel. I860, p. 144! 



Shell globose-depressed, thin, semitranslucent, unicolored or spir- 

 ally banded and dotted, the last whorl not descending in front; 

 aperture large, broadly lunate, the lip thin, not in the least expanded 

 or reflexed, dilated and appressed at the umbilical insertion. Type 

 C. cubensis Pfr. pi. 56, fig. 7. 



