1892.] LAND-SHELLS OF ST. HELENA. 269 



^a6. Sugarloaf Quarry (2^r<ora). Extinct. 

 This is a very minute species, with very oblique, slender, and 

 somewhat remote costulas and no teeth within the aperture. 



25. SUCCINEA SANCT^-HELEN^ (LcSSOu). 



Hab. High ground among native vegetation {Turton). Living. 



26. SucciNEA piCTA, Pfciffcr. 



Hob. All over Sugarloaf Ridge, common {Turton). Living. 



27. SucciNEA BENSONIANA, Forbes. 



Hab. Long Range, Sugarloaf Ridge, common, both living and 

 extinct (Turtoti). 



Little can be suggested with regard to the origin or relationship 

 of the above three species, for, as is well known, Succineas all the 

 world over have a remarkably strong family likeness. That they 

 are not importations of modern times, however, is proved by the fact 

 that one of them occurs in a semifossil condition along with other 

 extinct forms of land-shells. 



B. Introduced Species. 



Through the kinduess of Mr. E. L. Layard I have had the 

 opportunity of examioing the types of two of Benson's species, 

 namely : — Achatina veru and Bulimus compressilahris. The 

 former I regard as identical with the West-Indian CcBcilioides 

 gundlachi (PfeifFer), which is synoymous with Macrospira aperta 

 of Guilding from St. Vincent's, specimens of which, from Guilding's 

 collection, are now in the British Museum. As it was found in 

 the Public Gardens at Jamestown there is every probability of its 

 being a comparatively recent introduction along with West-Indian 

 plants. 



The Bulimus compressilahris also appears to be an introduction 

 from the West Indies, for it is identical with the Stenogyra ascendens 

 of Poey from Cuba, which I believe to be merely a slender form of 

 St. goodallii, Miller. The remaining introduced species have 

 been enumerated in the early part of this paper. 



EXPLANATION OF THE PLATES. 

 Plate XXI. 



Figs. 1, 1 a. Patula spurca, p. 260 

 2-2 b. dianm, p. 261. 



•persol'uta, sjs. n., p. 261. 

 Icstissima, sp. n., p. 261. 



3-3 J 



d - 1 b, t^ufii^t^iuuc, a|j. u.., p. ^j\j± 



5. bilamellata, p. 262. 



6-66. wrnoni, sp. n., p. 262. 



7-7 b. pseitstes, sp. n., p. 262. 



8-8 c. polyodon, p. 263. 



10-10 c. 



O— o c. —^ puiiyuauto, p. ^uo. 



9-9 c. miiiutissima, sp. n., p. 264. 



10-10 c. leptalea, sp. n., p. 264. 



Proc. Zool. Soc— 1892 No. XIX. 



19 



