THE CYCLOPHORID LAND MOLLUSKS OF AMERICA 131 



APEROSTOMA (CYCLADAMSIA) FOSSILE, new species 



Plate 18, Figuees 22-24 



Shell of medium size, helicoid, yellowish white. The nucleus con- 

 sists of a little more than one turn ; the next two turns are marked by 

 well-rounded, retractively curved axial riblets, which are a little wider 

 than the spaces that separate them. The next whorl is marked by 

 strong rough wrinkles at the summit. The rest of the whorls are 

 marked by retractively curved cords, which are slightly wavy and 

 slightly nodulose, producing a somewhat pitted effect on the general 

 surface. The last half of the last turn is very roughly sculptured. 

 The wrinkles at the summit are intensified, and the rest loses its 

 regular retractively curved ribbing, which is replaced with irregular 

 wrinkles, malleations, and pits. Suture well impressed. Periphery 

 well rounded. Base well rounded, broadly openly umbilicated with 

 a moderately strong cord marking the outer limit of the umbilicus. 

 The base of the early part of the last whorl is marked by the con- 

 tinuation of the axial cords referred to for the spire, and the same 

 type of pitting between them. The regularity of the disposition of 

 these elements disappears on the last half, where a similar type of 

 pitting and nodulation is present, but no regular distribution of these 

 elements obtains. The umbilical wall is marked by wavy strong axial 

 ribs. Aperture very large, somewhat channeled at the posterior 

 angle and slightly excavated on the columellar wall. Operculum 

 unknown. 



The type, U.S.N.M. No. 535987, and a large series of specimens, 

 U.S.N.M. No. 375436, were obtained by Mr. Orcutt from fossiliferous 

 sand sifting in a cave north of One Eye Kiver Sink, near Balaclava, 

 Manchester Parish, Jamaica. The type has 4.5 whorls and measures : 

 Height, 11.7 mm.; greater diameter, 18.2 mm.; lesser diameter, 

 13.9 mm. 



An additional lot, U.S.N.M. No. 397355, was obtained on a hill north 

 of One Eye River Sink below the cave in crevices in the precipice. 



This species belongs to the seminvdum group, as far as the type 

 of sculpture is concerned, but differs from it in the larger aperture 

 and the much stronger umbilical sculpture and also in having the 

 sculpture of the spire and base finer. It is evidently a fossil. Or- 

 cutt failed to find living specimens of it in the region. 



APEROSTOMA (CYCLADAMSIA) RUDISPLANUSQUE (Chitty) 



Plate 18, Figuees 13-18 



1857. Cyclotus rudis-planusque Chitty, Proc. Zool. Soc. London, vol. 25, p. 152. 



Shell small or medium sized, helicoid. When perfect, covered with 

 a wood-brown periostracum, which may be streaked with axial darker 



