1910.] NATURAL SCIENCES OF PHILADELPHIA. 533 



Aperture oval, the inner outline less curved than the outer. Peris- 

 tome thin, flatly reflexed, whitish with several brown spots, sometimes 

 indistinct, wider on the outer and basal margins, and having a barely 

 projecting inner rim. 



Length 9.5, diam. 4 mm., width of outer lip .3 mm., 5£ whorls re- 

 maining. 



Length 10, diam. 4.2 mm., apex entire. 



Length 7, diam. 3.2 mm., 4^ whorls remaining. 



Wesley Mount Church, near William sfield. Types No. 101,503. 

 A. N. S. P., collected by Dr. A. P. Brown, 1910. 



This species is closely related to R. campbelli (C. B. Ad.), but it is 

 very much slenderer, less robust, with a much more slowly tapering- 

 spire and without the strong spiral cords in the umbilical region 

 characteristic of R. campbelli. Seven specimens were taken, one 

 having the spire entire. 



The striae are undulated in the darkest specimens, but not notice- 

 able in the light ones. 



CYCLOPHORIDiE. 



This family is represented by a single genus in Jamaica. There 

 has been a good deal of uncertainty about the proper generic name 

 for the group among the several following: 



Aperostoma Troschcl, Zeitschrift fur Malakozoologie, IV, 1847, p. 44; cj. 



Pfeiffer, /. c, pp. 44 and 104. Fischer, Manual de Conchy liologic, p. 744; 



and von Martens, Biplogia Ccntrali Americana, Mollusca, p. 300 [type 



C. blanchetianus], 

 Crocidopoma Shuttleworth, Journal dc Conchyl., V, 1857, p. 271 (lor C. 

 floccosum and C. suturale) [type C. saturate], 



Playstoma M6rch, Malak. Blatter, VII, 1869, p. (i(i. Not Playstoma Meigen, 



1803. 

 Neocyclotus Fischer et Crosse, Mission Sci. au Mexique, Moll., II, p. 148 



[type C. clijsoni Pfr.]. 

 Ptychocochlis Simpson, Proc. U. 8. National Museum, XVII, 1895, p. 431, 



type Neoct/clotux jamaicensis. 

 Plectocyclotus Kobelt und Moellendorff, Cat. gegenw, Pneumonopomen, 



p. 138 (34) [type C. jamaicense Sowb.]. 



Aperostoma was proposed, as Fischer and Crosse have pointed out. 

 for three very diverse species, belonging to as many genera; but 

 Pfeiffer, in the same year commented upon this fact, and restricted 

 the group to American Cycloti, giving a list of the species. This 

 restriction was accepted by Fischer (1885) and by von Martens (1890). 

 The genus Neocyclotus was therefore superfluous. Crocidopoma seems 

 to us to be only a subgenus of Aperostoma, not a separate genus. 



For the group of corrugated Jamaican species the subgeneric term 

 Ptychocochlis Simpson should be used. Plectocyclotus Kob. et Mlldff. 

 s an absolute synonym. 



