140 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



COIiOBOSTYLUS (COr,OBOSTYL,OIDES) SAXOBUM (Weinland) 



Plate 21, Figure 1 



1862. Cyclostoma saxorum Weinland, Malak. Blatter, vol. 9, p. 88. 



1888. Colohostylus saxorum Crosse and Fischer, Journ. Conchyl., vol. 36, p. 234. 



Shell ovate, when truncated almost pupiform. Nuclear whorls de- 

 collated in all our specimens. Postnuclear whorls strongly rounded and 

 marked by strong, narrow, somewhat retractively slanting axial ribs, 

 which are expanded into auricles at the summit. Of these ribs, lOO are 

 present on the last whorl in the specimen figured. Suture slightly chan- 

 neled. Periphery well rounded. Base narrowly openly umbilicated and 

 marked by the continuation of the axial ribs, which extend also over 

 the umbilical wall. Aperture almost circular; peristome double, the inner 

 somewhat exserted and slightly reflected ; the outer moderately expanded, 

 somewhat auriculated at the posterior angle where it is a little wider 

 than the rest, which is of uniform width. Operculum large — too large 

 to be withdrawn within the aperture, with the nucleus halfway between 

 marginal and central. The whorls of the operculum bear a lamella whose 

 outer edge touches that of the succeeding turn thus forming a continu- 

 ous surface. The lamella is marked by fine, retractively curved hairlines. 



The specimen figured (U.S.N.M. No. 425692) is one of 2 cotypes 

 received from the Senckenbergisches Museum. It has 3.4 whorls re- 

 maining and measures : Height, 7.2 mm. ; greater diameter, 5.0 mm. ; 

 lesser diameter, 4.8 mm. The type was described from Jeremie, Haiti. 



U.S.N.M. No. 380328 contains 13 specimens collected by W. J. Eyer- 

 dam on a rock pile 3 miles north of Pestel, Haiti. 



Genus ROLLEIA Crosse 



1891. Rolleia Crosse, Journ. Conchyl., vol. 39, pp. 162-163. 



Shell decidedly depressed-helicoid, with the last whorl decidedly solute. 

 Whorls strongly rounded, marked by axial ribs only. Base very broadly 

 umbilicated. Aperture circular; peristome double. Operculum with a 

 thin calcified lamella which rises slightly obliquely then bends more 

 rapidly at the outer third. The whorls of the lamella are separated by a 

 broad space which is also slightly calcified and is crossed by distantly 

 spaced axial riblets. 



Type species : Cyclotus vmrtensi Maltzan = Rolleia martcnsi ( Malt- 

 zan). 



KEY TO THE SPECIES OF ROLLEIA 



Axial ribs very closely spaced martensi 



Axial ribs not very closely spaced haitensis 



ROLLEIA MARTENSI (Maltzan) 



Plate 23, Figures 4-6 



1888. Cyclotus martensi Maltzan, Nachr. deutschen malak. Ges., vol. 20, p. 179. 

 1891. Rolleia martensi Crosse, Journ. Conchyl., vol. 39, pp. 163-164, pi. 2, fig. 4. 



Shell very depressed-helicoid, almost lenticular, with the last whorl 



