1892.] LAND-SHELLS OF ST. HELEVA. 259 



collection, and for the careful notes regarding localities which accom- 

 pany the specimens. 



The most complete account of the terrestrial fauna ^ of St. Helena 

 hitherto published is that given by Mr. "VVollaston in his work 

 'Testacea Atlantica,' published in 1878. He there enumerates 29 

 species of Land- Shells, of which 9 at least must be regarded as 

 introductions since the discovery of the island 390 years ago. Some 

 of these species — for example, Limaco gagates, Vitrea cellaria, V. 

 alliaria, Helix pulchella, H. aspei'sa, and Pupa umbilicata { = helen- 

 ensis, Pfr.) — were doubtless introduced along with European shrubs 

 and plants. Patula pusilla probably was imported from Madeira, 

 the Canary Islands, or the Azores, where it is very abundant ; and 

 the two remaining species, Stenogyra compressilabris and Acicula 

 veni, upon which some remarks will be made at the end of this 

 paper, are evidently West-Indian forms. With regard to the twenty 

 indigenous species mentioned by Mr. Wollaston, some, in my 

 opinion, are merely varieties and not specifically distinct. After a 

 careful study of all the forms, including the eleven new species 

 now described, the total number of indigenous species may be 

 estimated at twenty-seven. Of these, seven are living on the island 

 at the present time, eighteen have become extinct since the destruc- 

 tion of the primaeval forests, and two are found both recent and semi- 

 fossil. 



A great deal has been written upon the relationship of the fauna 

 of St. Helena with regard to other parts of the globe, and an 

 interesting resume of this subject is given by Mr. Wallace in his 

 work ' Island Life,' pp. 281-297. 



Professor Forbes many years ago, from a study of the Mollusca, 

 hazarded the theory of a possible ancient connection of St. Helena 

 with South America. This view, however, was vigorously rejected 

 by Wollaston, Jeffreys, and others, and, considering the present 

 isolated position of the island, the actual enormous depth of the 

 surrounding ocean, and other cogent reasons ', this theory certainly 

 does appear unsupportable. There is, however, a greater resem- 

 blance between the shell-fauna of the two localities than was recog- 

 nized either by Forbes or Wollaston ; and the occurrence of a species, 

 discovered since they investigated this subject, and more resembling 

 a group {Tomigerus) which is exclusively Brazilian in distribution 

 than any other, together with the reasons which influenced Forbes, 

 would seem to indicate that country as the probable source whence 

 some of the indigenous but now extinct species, or their ancestors, 

 originated. How they were transm.itted is a hopeless problem to 

 solve, and although drift-wood, carried by oceanic currents, is 

 doubtless answerable for a good deal in the way of disti*ibution, the 

 subject must apparently ever remain one of mere speculation. It 

 has been stated by Mr. Wollaston that the large Bulimus auris- 

 vulpina is represented in the Solomon Islands and New Zealand by 



^ No freshwater forms have as yet been discovered. 



^ Neither the flora of St. Helena nor the insect-fauna suggests particularly a 

 South-American relationship or origin. 



