No. 2327. THE ANNULARIIDAE— HENDERSON AND BARTSCH. 79 



The following species are now referred to this subgenus. They 

 fall into two groups as follows: 



The group of Eutudorops azucarensis: 



Eutudorops azucarensis, new species Western Cuba . 



The group of Eutudorops torquatum: 



Cydostoma torquatum (Gutierriez) Poey Central Cuba. 



Genus RAMSDENIA Preston. 

 1913. Ramsdenia Preston, Proc. Malac. Soc. London, vol. 10, p. 323. 

 Shell elongate-conic, marked by slender wavy sublamellar axial 

 riblets and obsolete spiral cords. The riblets are gathered into irreg- 

 ular tufts at the summit. Operculum with the calcified lamella 

 arched convexly over the entire whorl, marked by slender retract- 

 ively curved threads. 



Type of the genus. — Ramsdenia mirijica Preston. 

 The following species are now referred to this genus : 



Ramsdenia mirifica Preston Eastern Cuba. 



Cydostoma nobilitatum (Gundlach) Poey Eastern Cuba. 



Rhytidopoma tolleni Ramsden Eastern Cuba. 



Ctenopoma bu/o Pfeiffer Eastern Cuba, 



Ctenopoma perspedivum (Gundlach) Pfeiffer Eastern Cuba, 



Ctenopoma semicoronatum (Gundlach) Pfeiffer Eastern Cuba. 



Genus DIPLOPOMA Pfeiffer. 



1859. Diplopoma Pfeiffer, Malak. Blat., vol. 6, p. 73. 



Shell elongate-ovate to elongate-conic, marked by strong axial 

 riblets and spiral threads. Operculum with the calcified lamellae 

 reflected to parallel the basal plate. The lamellae marked by strong 

 retractively slanting riblets. The outer surface of the operculum 

 may be flat or convex. 



Type of the genus. — Diplopoma arcJiitectonicum (Gundlach) 



Pfeiffer. 



Subgenus DIPLOPOMA Pfeiffer. 



1859. Diplopoma Pfeiffer, Malak. Blat., vol. 6, p. 73. 



Shell almost turbinate to elongate-conic, marked by strong axial 

 riblets and spiral thi'eads. Operculum flat, with the calcified lamellae 

 reflected to parallel the basal plate. Lamellae marked by strong 

 retractively slanting riblets. 



Type of tJie subgenus. — Biplopoina arcJiitectonicum (Gundlach) 

 Pfeiffer. 



The following species are now referred to this subgenus. They 

 fall into two groups, as f oDows : 



The group of Diplopoma retrorsus: 



Cydostoma retrorsus C. B. Adams Jamaica. 



Cydostoma moussonianum C. B. Adams Jamaica. 



Cydostoma radiosum Morelet Guatemala . 



