in the year 1778 who found the natives using them for orna- 

 mental purposes. The wide range of color they displayed led 

 to numerous descriptions of supposedly new species, so when 

 Dr. Pilsbry undertook his monographic revision of the group 

 in 1912 he found the record cumbered by the presence of 171 

 trivial names that had been applied to various forms. In his 

 revision he reduced the number of recognized species to 43. 



In the meantime Gulick (1908), had called attention to the 

 theoretical interest attaching to the achatinellids as a remark- 

 able example of microgeographical speciation. The snails, liv- 

 ing on the trunks of trees and relatively non-migratory, tend 

 to form large numbers of inbred local races. Gulick interpreted 

 these racial differences as due to isolation and random varia- 

 tion in the ancestral stock, the observable differences having 

 no selective value; in other words a form of evolutionary pro- 

 gression in which the Darwinian principle of Natural Selection 

 was not involved. Pilsbry offered the further suggestion that 

 in these local races we have phenotypes representing Mendel- 

 ian segregates. Both of these views are quite in line with our 

 present interpretation of the phenomena. 



The studies of Gulick and Pilsbry based upon the Hawaiian 

 tree snails were followed by the investigation by Crampton 

 (i9i6),ofthe terrestrial snails included in the genus Partula 

 inhabiting Tahiti. He found that in this island, as in Oahu, 

 there were a large number of microgeographical areas which 

 were inhabited by local races of the snails. He did not find 

 any differences in the environmental conditions which would 

 suggest that a selective process was involved in deteripining 

 the development of racial speciation. 



More recently Welch (1938, 1942), has made a very detailed 

 study of the achatinellid fauna of the island Oahu, pinpoint- 

 ing the microgeographical distribution of the numerous local 

 races in great detail. He reduces the number of recognized 

 species to six, and gives all of the clearly defined local races 

 the status of subspecies, some of which have assigned to them 

 as many as seven unnamed varieties. In the case of one of 



