316 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



elevated above the outer, slightly reflected and appressed to it. The 

 breathing pore is at some little distance behind the peristome on the 

 parietal wall and close to the posterior angle of the aperture. The 

 operculum is thin, paucispiral, with submarginal nucleus, the outside 

 covered with a thin deposit of fine calcareous granules. 



This species was found abundantly on the limestone cliffs and 

 talus slopes on the north side of Mount Guajaibon, near the western 

 end of the mountain, Pinar del Rio, Cuba. 



The specimen described and figured is a complete individual, hav- 

 ing 6.0 whorls, and measuring: Length, 14.2 mm; greater diameter, 

 10.2 mm; lesser diameter, 7.5 mm. 



The chubby shape, fine sculpture, and dark color pattern with the 

 brilliantly contrasted peristome give this race a very distinct aspect. 



This species was described by Orbigny in 1842 in Sagra's Histoire 

 de I'lle de Cuba, vol. 1, pp. 259-260, and figured on plate 22, figures 

 6, 7, and 8", but not 8 or 8'. Figures 8 and 8' represent an operculum 

 belonging to Rhytidothyra hilahiata Orbigny, the shell of which is 

 figured on the same plate as 3, 4, and 5, but without operculum. The 

 case simply represents a transposition of the operculum from the one 

 species to the other. Morelet, failing to recognize this transposition, 

 renamed the shell Cyclostoma sericatum. 



CHONDROTHYRELLA (CHONDROTHYRELLA) PERTURBATA, new species 



Plate 24, Figure 2 



Shell very broadly ovate, the nuclear tip with an orange initial 

 portion followed by horn-colored turns. The postnuclear whorls are 

 bright orange, which usually becomes diluted on the last or some- 

 times the last two turns. Peristome pale yellow. Nuclear whorls a 

 little more than 2, strongly rounded, smooth ; the postnuclear whorla 

 are inflated, strongly rounded, and marked by slender, retractively 

 slanting, axial riblets and stronger spiral threads. The intersection 

 of the two forms elongated nodules whose long axis corresponds with 

 the axial sculpture. The spaces enclosed between the axial riblets 

 and the spiral threads are rectangular pits, having their long axis 

 also in agreement with the axial sculpture. Suture strongly im- 

 pressed ; periphery inflated, strongly rounded. Base inflated, strongly 

 rounded, and marked like the spire. Aperture very broadly oval; 

 peristome double; the inner slightly exserted and appressed to the 

 outer, which is broadly flaringly expanded, somewhat fluted and 

 marked by slender concentric lamina. The outer peristome is cut in 

 the middle of the inner lip and the posterior portion is reflected over 

 the umbilicus as a broad flap, completely closing this. The parietal 

 wall is covered with a heavy callus. Operculum thin, paucispiral, 

 corneous, with a heavy deposit of calcareous granules. 



