PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



by the 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 



Vol.85 Washington: 1938 No. 3039 



THE CUBAN OPERCULATE LAND SHELLS OF THE 

 SUBFAMILY CHONDROPOMINAE 



By Carlos de la Torre and Paul Bartsch 



INTRODUCTION 



In all tlie world there i.s no place of equivalent area that has a 

 o-reater number of si)ecies and races of land shells than the Island 

 of Cuba. It is a veritable paradise for the lover of mollusks, for we 

 find not only a numerical preponderance but also beauty of outline 

 and coloration rivaling the faunas of the Philippine and Hawaiian 

 Islands. 



The interesting features presented by this fauna are not restricted 

 in appeal to the systematic zoologists — taxonomists — for here the 

 student of genetics and heredity also will find a veritable laboratory 

 teeming with an endless number of problems inviting solution. 



In Pinar del Rio Province, in western Cuba, the Organ Mountains, 

 because they are broken up into isolated blocks and by the even greater 

 cutting up of the lateral folds to the north and south, now^ largely 

 represented by the series of mogotes — hills — of varying size into which 

 the teeth of time have cut them, show splendidly in their faunas the 

 effects of isolation and inbreeding, resulting in an almost endless array 

 of races, each confined to a limestone cliff, which may vary in size from 

 a barn door to miles in extent. 



To such restricted habitats most of the members of the subfamily 

 Chondropominae are more firmly wedded today than they would bo 

 if they occupied equally distant islands, from which they might be 

 carried by currents or waves to neighboring shores, for gi'assy inter- 

 vals present a greater barrier to these calciphil dwellers than would 

 the open sea. As we see it, there are only two agencies at present 

 liiat might serve as carriers from place to place, wind and birds, 



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