the Land and Fresh/cater Shells of Barbados. 249 



In the case of ihe Slreptaxis^ Bulimus ohlonguSj pcrliajw of 

 all the Jjulimuli, the Orthcdicus, the Playiorbis, and the Pala- 

 destrina, we may eonjecture that they have spread northward 

 to the islands, from the faet that those genera are more 

 numerous in species on the mainland. On the other hand, 

 we may suppose that the Sleno<jyrw and the Leptinaria have 

 migrated southward from the islands to the continent, as the 

 species in question, Leptinaria lamellata^ St. octona, and St. 

 JJeckiana, appear, as far as we know at present, to be more 

 common in the islands. This is somewhat conjectural, as our 

 knowledge respecting the distribution of any of these species- 

 is doubtlessly very incomplete, and we do not know the 

 relative abundance of them in the various localities where 

 they have been found. 



Bidimus ohlongus and the Orthdlicus are said to have been 

 introduced by direct personal agency, and in all probability 

 the presence ot others is attributable to the same cause. Tiie 

 introduction of trees and plants from one place to another 

 affords an easy way for the transmission of land-shells either 

 in the egg-stage or even as adult specimens. 



1. Vitrea inclsa (Pfeiffer). 



Helix incisa, Pfeiffer, Mai. Blatt. 18(56, vol. xiii. p, 78 ; Muuogr. llel. 

 vol, V. p. 107. 



ILab. Barbados. 



This species was described from Barbados from specimens 

 obtained by Mr. Theodore Gill. It is a very depressed form, 

 with a flattened spire, and remarkable for the distinct impressed 

 lines of growth which divide the last whorl into numerous 

 scc;meiits. 



2. Helix [Dentellai'ia) perplexa^ Ferussac. 



Helix iierpkxa, Ferussac, Hist. iiat. Moll. vol. i. p. 378, pi. Ivi. a. 



%. 1. 

 UelLv (jranifcra, Gray, Pfeiffer, Conch. -Cab. ed. 2, pi. Ixii. ligs. 10, 17; 



Reeve, Conch. Icou. pi. lii. figs. 252 a, b, pi. clxxvii. fig. 1210 (as 



perplexa). 



llah. Grenada, Trinidad?, Barbados. 



This species has not been previously recorded from Bar- 

 bados ; but some specimens, presented to the Britisii Museum 

 by iSir liawsou llawson in 1870, w^cre said to iiave come from 

 that locality. 



