HYATT: GENEALOGY OP ACHATINELLID^. 371 



portant species, the Boston Society's collection of about 

 4,000 shells and a collection of about 4,500 shells lent by 

 Eev. Harcourt W. Peck. I have also had the benefit of study- 

 ing the collections of the Smithsonian Institution and Na- 

 tional Museum, Academy of Sciences of Philadelphia and the 

 Museum of Comparative Zoology at Harvard, as well as tem- 

 porary loans for examination, the collections of Cornell Uni- 

 versity. Rev. J. T. Gulick, Mr. D. D. Baldwin and Mr. C. M. 

 Cooke, Jr., have also materially helped me by the benefit of 

 their great knowledge of the species in the field. To Hon. 

 W. DeW. Alexander, Rev. Oliver P. Emerson, Mr. A. B. 

 L/yon, the U. S. Coast Survey and to others I am also in- 

 debted for material assistance in procuring maps and in- 

 formation necessary for my work. 



The land shells peculiar to the Hawaiian Islands are of 

 remarkable interest in connection with problems of evolution 

 and heredity, since they are an extensive group wholly con- 

 fined to these islands, and consisting of about 400 species. 

 Many of these exhibit permanent varieties, and are repre- 

 sented by immense numbers of individuals. The field is 

 practically occupied by these peculiar species to the exclusion 

 of other more cosmopolitan groups of land shells which are 

 represented by only about 111 species, and these are not so 

 numerous in individuals. 



The Hawaiian Islands are arranged in an almost linear 

 arc of about 400 miles extending from Kauai and Niihau at 

 the northwestern, to Hawaii at the extreme southeastern end. 

 Their existence is due to volcanic elevations and eruptions. 



The relative age of each island has been determined by 

 geologists, and I find that the relative age, and evolutionary 

 development of the faunas, is commensurate with the age of 

 each island. 



By pursuing the study of the faunas closely, I determined 

 what appeared to be their natural course of evolution and 

 apparent succession. A study of the phylogeny of the faunas 

 appeared to demonstrate that Kauai, the northwesternmost 

 of the chain, had the most primitive fauna, Oahu having the 

 next in succession, while Molokai, Lanai and Maui although 



