Descriptions of New Species of Hklicidte. 17 



yellowish brown spots above and lines beneath ; spire obtuse ; 

 whorls ?5 ; very slightly convex, last one obtusely carinated, 

 not deflected, convex beneath; umbilicus moderate; aperture 

 lunar, strengthened within by a sharp but strong white lamella 

 which revolves beneath the periphery, and is plainly visible 

 through the substance of the shell, throughout the last whorl ;. 

 columella very oblique^, thickened into a callus which extends, 

 inwardly around the umbilical portion of the shell ; lip simple^ 

 acute. 



Greater diameter 0,42 inch (11 millim,). Lesser do. 0.39 inch 

 (10 millim.). 



Height 0.24 inch (6. millim.). 



Habitat. Bermuda, where it is rarely found under stones in 

 plantations on the hill near St. George's, in company with Helix 



microdonta Desh., Bulimus ventrosus Fer.,^ Helicina , and 



Succinea . It has been collected by our associates, Mr. 



T. Bland and Mr. T. Prime, by Mr. Eobert Swift of St. Thomas. 

 and also by the late Prof. Adams. 



* The occurrence of Bulimus ventrosus Fer. at Bermuda, has, we believe, not 

 been before noticed, and is an interesting fact as exhibiting an area of habitat 

 very unusual in a terrestrial species. Its occurrence is now authenticated 

 at the following points : Southern France, Draparnaud, Lamarck, and others ; 

 Italy, Lamarck; Southern Greece, Deshayes ; Portugal, Morelet ; Barbary, 

 Terver ; Madeira, Lowe ; Canary Islands and Azores, Orbigny, Webb and Berthe- 

 lot ; Bermudas, Swift, Bland, Prime, and Adams. This general insular distribu- 

 tion is peculiarly remarkable, and it seems difficult to account for this exception 

 to a well known law, except by bringing in the aid of human agency. The early 

 colonization of the Madeiras and Canary Islands by the Portuguese, could easily 

 occasion the accidental introduction of small European species of terrestrial shells 

 and we accordingly find other instances of a similar kind in the fauna of those 

 islands. This might also happen in the Azores, distant as they are; but in the 

 case of the Bermudas, this probability is much lessened by the fact of their colo- 

 nization, trade, and communication having been mostly confined to Great Britain, 

 where this species does not exist. 



MAY, 1853. 2 Ax? *- LTC - NAT - HIST - VoL ' Vf - 



