416 PROCEEDINGS OF THE ACADEMY OF [1896. 



demonstrate their identity. The species of Stenogyra are obviously 

 West Indian or continental and call for no special remark. 



The land shells of St. Helena have been described by Smith (P. 

 Z. S., 1892, pp. 258-270), from collections by Captain W. H. Tur- 

 ton R. E. The National Museum is indebted to Captain Turtonfor 

 a nearly complete series of his St. Helena shells, including one 

 or two species accidentally introduced since the settlement of the 

 island. These have proved of great value for comparison, as the 

 best figures fail to give the peculiarities of surface texture with 

 which, in this discussion, we are largely concerned. Omitting syn- 

 onyms, mere varieties and recently introduced species, the land shell 

 fauna of St. Helena comprises four species of helicoid shells without 

 lamellae, which have been referred to Patula but which may prove 

 to be edentulous species of Endodonta, ten* species of Endodonta 

 (section Helenoconcha Pilsbr}'^) with more or less complicated oral 

 lamellre ; Achatina (PacJujottis) auris-vulpina Dillw., and two or 

 three related species ; Achatina {Cleostyla) exulataand suhtriincata ; 

 Bulimulus {Pachnodus') helena and two related species ; a Tomigerus- 

 like sheW, Papa {Camp olaemus) perexilis (Smith) Pilsbry, and two 

 minute species of Pupa ; and, lastly, three species of Succinea, in all 

 twenty-nine species. Of these, by the gradual desiccation of the 

 island, twenty-two are become extinct. 



The native forms found living comprise two species of Endo- 

 donta, Pachyotus melanoides and P. Turtoni, and three species of 

 Succinea. The mollusk fauna as a whole, is Oceanic, and shows no 

 strong affinity with either America or West Africa, especially the 

 former. The manner in which these mollusks reached the island is 

 a mystery, the more so as it is said that the flora and insect fauna 

 also show no special relationship with those of South America. 

 Nevertheless, the contours of the sea bottom as well as certain feat- 

 ures of the fauna indicate a previous more intimate relation between 

 South America and Africa than has recently existed, and, whatever 

 this bond may have been, it is not improbable that St. Helena par- 

 ticipated in it. Any ordinary means of transport would seem to be 

 insufficient to account for the presence of Pachyotus, of which even 

 the eggs are six millimeters long. We are not obliged for present 

 purposes to concern ourselves with this problem of origin. The in- 



* H. Alexandri Forbes and polyodon Sby., are both represented in Captain 

 Turton's series and are distinct species ; a single specimen of a species appar- 

 ently undescribed also occurred among those sent to the National Museum. 



