184 



CEPOLI8. 



with a large split inner cusp and a simple or bifid ectocone (pi. 57, 

 figs. 50, 51, C. varians*). 



Genital system having a long, slender penis branching into v. d. 

 and a long flagellum, and with a thread-like retractor attached low, 

 and inserted distally on the lung floor. Spermatheca duct free 

 below, but firmly bound to uterus above, with a long spermatheca 

 and a spiral twist in the duct near base of uterus. Dart sack long ; 

 mucus glauds two, flat and glandular, inserted at base of dart sack- 

 Eye stalk retracted between branches of geuitalia (pi. 52, fig. 14, C. 

 varians Mke.). 



The shell in this section differs but little from that of Coryda and 

 Dlnleuca ; and while quite distinct from the typical forms of Pla- 

 gioptycha, there are a number of species so intermediate in character 

 that they may be placed as well in one as in the other group. Ana- 

 tomically there are no differences of more than specific worth 

 between these groups, unless the larger (though still very weak) 

 penis retractor of Hemitrochus be considered such. Many of the 

 species are excessively closely allied. 



There are two groups of species: the Cuban, consisting of com- 

 pact forms of the type of H. cesticutus; the Bahama group varying 

 from globose-conical like H. varians to depressed and rib-striate, H. 

 maynardi. 



Species of Florida and Bahamas. 



C. varians Mke., v, 24. 



carnicolor Pfr. 



submeris Migh. 



rhodocheila Binn. 



polychroa Binn. 



hcKmnstomus Sw. 

 C. xanthophaes Pils., viii, 242. 

 C. milleri Pfr., v, 25. 

 C. constantior Weinl., v, 26. 

 C. caribsea Weinl., v, 26. 



C. gallopavonis Val., v, 27. 



v. calacaloides Pils., v, 28. 

 C. troscheli Pfr., v, 28. 

 tenuicostata Dkr. 



v. calacala Weinl., v, 29. 

 C. mulrlfasciata W. & M., v, 30. 



f. polytreniata Pils., v, 30. 

 C. filicosta Pfr., v, 30. 

 C. brownii Pils., v, 29. 

 C. maynardi Pils., viii, 241. 



Cuban Species. 



C. gilvaFer., v, 31. 

 corrvgata Pfr. 

 v. tephrites Morel., v, 31. 



C. fuscolabiata Poey, v, 34. 

 snbfusca Poey not Bk. 

 v. morbida Morel., v, 35. 



