-THE CYCOLOPHORiD LAND MOLLUSTtS OP AMERTCIA 207 



3 specimens from the vicinity of Seeanquim, Alta Vera Paz No. 

 271019, 5 specimens from Myra Farm, Quirigua ; No. 250694, 3 speci- 

 mens from Finca de Providencia. 



The following four are without specific locality: U.S.N.M. No. 

 57769, 4 specimens; U.S.N.M. No. 162314, 8 specimens; "U.S.N.M. 

 No. 316392, 2 specimens, and U.S.N.M. No. 316390, 2 specimens. 



This subspecies shares with A. (N.) dysoni matanense the fine, 

 closely spaced vermiculation and the bicolor base, but it differs from 

 it in being much larger. 



APEROSTOMA (NEOCYCLOTUS) DYSONI RUATANENSE, new subspecies 



Plate 28, Figures 7-9 



Shell moderately large, helicoid, covered with a dark straw-colored 

 periostracum ; when denuded, soiled white. The nucleus consists of 

 2 small, well-rounded smooth turns. The postnuelear whorls are 

 strongly rounded, slightly bent in toward the suture at the summit, 

 and marked by strong axial anastomosing retractively curved ver- 

 miculations, which are separated by spaces about as wide as the 

 riblets. Suture strongly impressed. Periphery well rounded. 

 Base narrowly openly umbilicated, somewhat inflated, well rounded, 

 and marked like the spire, except the umbilical wall, which is marked 

 by riblike incremental elements. Aperture circular, except a slight 

 angulation at the posterior angle; peristome simple, thin on the 

 outer lip and thickened on the columellar side. A strong callus 

 covers the parietal wall. There is a groove between this callus and 

 the preceding turn, which gives the peristome a complete aspect. 

 An oval incised sinus is present on the parietal wall. Operculum 

 typically neocyclotid. 



The type, U.S.N.M. No. 364702, was collected by F. J. Dyer on 

 Kuatan Island, Honduras. It has 4.2 whorls and measures : Height, 

 13.3 mm.; greater diameter, 19.7 mm.; lesser diameter, 14 mm. 

 Height of aperture, 9.6 mm. ; diameter, 9.5 mm. 



This race resembles A. {N.) dysoni hinkleyi in sculpture and in 

 the bicolor basal coloration but is easily distinguished from this by 

 lacking the impressed groove below the summit and by its much 

 smaller size. 



APEROSTOMA (NEOCYCLOTUS) DYSONI DYSONI (Pfeiffcr) 



Plate 28, Figubes 28-30 



1851. Cyclostoma dysoni Pfeiffeb, Proc. Zool. Soc. London, vol, 19, p. 243. 



1852. Cyclophorus dysoni Pfedter, Monographia pneumonopomorum viventium, 



vol. 1, p. 98. 



1853. Cyclostoma dysoni Pfeipfee, Martini-Chemnitz Conchylien Cabinet, vol. 



1, sect. 19, p. 259, pi. 35, figs 5-6. 



