Synopsis of the Genus AcJtatinella. 303 



XXXVI. — Synojysis of the Genus Achatinella. 



By "W. Newcomb, M.D., of Albany, N. Y., Corresponding Member. 

 Read September 6th, 1858. 



In the Proceedings of the Zoological Society of London, of 

 August, 1845, Dr. L. Pfeiffer gave a list of eighteen species of 

 Achatinella, as then known to the scientific world. 



In the Proceedings of the Boston Natural History Society, 

 some six months anterior to this date, Dr. Mighels described 

 six new species, and Dr. Gould added four additional ones ; but 

 of this number several are included under different names in 

 Dr. Pfeiffer's Monograph. 



In 1850, Mr. Reeve gave ten or more new species in his 

 Monograph, to which we must add several species described by 

 Dr. Gould, and Professor C. B. Adams, swelling the numbers 

 known at this date to about fifty. 



From this point more laborers entered the field of discovery, 

 and the new forms since described have increased the known 

 species to more than one hundred and eighty. As several par- 

 ties were engaged at the same time in these labors, it is not at 

 all surprising that many species were repeatedly described 

 under different names, which has led to much confusion in 

 their arrangement. To obviate this difficulty, I have at the 

 solicitation of many friends consented to supply a synopsis of 

 the genus, as it now stands ; and have given, in addition, de- 

 scriptions of many of the animals, to aid in a correct diagnosis 

 of species. 



A residence of several years upon the Sandwich Islands, 

 with a careful study of this branch of natural history during a 

 period of nine years ; an opportunity for examining the origi- 

 nal types of Ferussac, Swainson, Gray, Reeve, and Pfeiffer, in 

 the great collections of Europe, together with the privilege 

 kindly afforded me by Mr. Gulick, of critically examining all 



SEPTEMBER, 1858. 22 Akn * Lt0, Nat> Hkt - Vol - VI - 



