X. — The Air-breathing Mollusks op the Bermudas. 

 By Henry A. Pilsbry,' 



The land-snail fauna of the Bermudas is one of considerable interest 

 from the isolation of the islands and their typical " oceanic " charac- 

 ter. Their small extent and low altitude have not favored the 

 development of a rich fauna, and in 1852, the date of the first list, 

 some exotic snails had already become established there. Coloniza- 

 tion proceeded until now the immigrants outnumber the original 

 Bermudians in the roll of Stylommatophores. 



Origin of the Bermuda Fauna. 



The fauna of air-breathing mollusks of the Bermudas is divisible, 

 in respect to origin, into three groups of forms. 



(a) Autocthonous species, peculiar to the islands. 



(h) Drift waifs from the "West Indies. 



(c) Species imported by the agency of man. 



The first group includes a single Thysanophora [hypolepta) and 

 one Helicina [convexa), both of Antillean type, and the genus 

 Poecilozonites with four species and several varieties.'' The relation- 



' This paper is based upon the collection made by Professor Verrill and party in 

 1898, that of Professor Heilprin's class who visited Bermuda in 1888, that of Robert 

 Swift, and specimens from the collections made by Thomas Bland and C. B. Adams. 

 Professor Verrill has added the results of his personal observations on many species, 

 greatly increasing the value of the study. 



- The species are P. bermudensis, nelsonl, reinianus and circumfirmatus. The genus 

 Pcedlozonites was supposed by its founder to include the recent Helix bermudensis 

 and the German lower Miocene Helix imbricata Braun. In a former paper on Ber- 

 mudian Helices I had occasion to show that several other Bermudian species belong 

 to Pcedlozonites, and I would hero record my belief that in bringing a European 

 Miocene species into the Bermudian group. Dr. Boettger is only chasing an ignis 

 fatuus. The pursuit of false lights has led most of the Germans who write on 

 Helices into a maze of quagmires. "Whether dealing with fossil or recent forms, 

 their ideas on classification, and consequently on zoogeographic and palceontologic his- 

 tory also, are so hopelessly astray that the only path to redemption is for the young 

 men to break away from the blind leaders of the blind, and seek solid footing. 



Trans. Conn. Acad., Vol. X. September, 1900. 



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