348 Geographical Distribution 



(the same being found in India) in St. Thomas and Trinidad. 

 Strophia, winch occurs in Portorico, lias a semi-fossil species in 

 St. Croix, but disappears in the islands east and south of Por- 

 torico, with the solitary exception of S. uva in Cui'a^ao. The 

 ishmds above-mentioned as being related to Portorico, have, in 

 common with many of those south of Angnilla, species of 

 Bulimi which also occur in South America.* 



St. Christopher, Antigua, the French islands, and those fur- 

 ther south, are all more or less connected inter se, and in a 

 marked manner with South America. The preponderance of 

 Bulimus, and the paucity of operculated genera and species, 

 are noticeable. No representative of the family Cyclostomacea 

 has yet been found in Barbados. The single Streptaxis, dis- 

 covered by Mr. Gill in 1859, occurs in Trinidad. Plecochilus 

 (a subgenus of Bulimus), characteristic of South America, only 

 inhabits the islands east and south of Portorico, with the excep- 

 tion of one s])ecies, I^. glaher, attributed, but I think erroneously, 

 to Haiti. Stenopus, a subgenus of Nanina (separated from 

 Helix), is peculiar to St. Vincent. The number of species com- 

 mon to the French 'West India Islands, and French Guiana, 

 but absent in the intermediate islands, as shown by Drouet 

 (Vide Jf<il. Blait, 1860, p. 126), is remarkable. In connexion 

 Avith the fact that the Spanish Islands of Cuba and Portorico 

 have more species in common than either has with Haiti which 

 lies between them, can the partial similarity of faunas be attri- 

 buted to increased intercourse between the inhabitants belonof- 

 iog in modern times to the same European nation ? Some of 

 the species common to the continent and islands, and to more 

 than one island, are, size and habits considered, such as are most 

 likely to have been distributed by human agency. 



On the whole, Portorico, with Vieque, and the islands east- 

 ward towards Angnilla, may be considered as forming a dis- 

 tinct province, and the remaining islands, more to the south, as 



* Woodward (Manual, p. 388) remarks on several species common to St. Tho- 

 mas and the Canary Islands, but none such exist. 



