smith: N-ON-MAEINE MOLLTISCA of ST. VINCENT. 301 



to, Streptaxis {Ammonoceras) Thomasi, was originally described from 

 'New Granada. As Mr. Smith also collected it in Grenada, tlie 

 possibility suggests itself that the type specimens may have come from 

 that island and not from New Granada. 



Some doubt exists with regard to the occurrence of two or three 

 of the listed species at St. Vincent ; at all events, it is many years 

 since they have been recorded from the island. Among these may 

 be mentioned Bulimidus Vmcentinus^ B. limnoides, B. exilis, and 

 Amphihuli ma tigrina. 



A number of specimens in the British Museum are labelled 

 "St. Vincent," and were purchased in the year 1839 at the sale of 

 Guilding's collection. On investigation, however, there is no evidence 

 of their having been obtained from that island. It seems probable 

 that this locality was assigned to them, from the fact that Guilding 

 resided there for some time. Unfortunately, some of these have 

 already been quoted in one or two of the writer's own papers, e.g., 

 Bulimulus tenuissimtis, CyHndrella costata, Helicina siibstriata, and 

 Helicina fasciata. Those, therefore, should be struck out of the 

 St. Vincent fauna. The following table will show at a glance the 

 distribution of the various species. It will be noticed that only four 

 out of the thirty-eight enumerated are, as far as we know at present, 

 peculiar to the island, and there is every probability that most of these 

 will eventually be discovered in other localities. 



The relationship of the fauna of St. Vincent to that of the 

 neighbouring islands appears to sustain the deduction that this 

 island and the group of islands to the south, as far as and 

 including Trinidad, rest upon a " submerged ridge " or extension off 

 the north part of the South American continent.^ Fifteen of the 

 St. Vincent species are found in Grenada and eleven in Trinidad, and 

 eleven range as far as the mainland. Only seven species are common 

 to St. Vincent and Barbados, and only four to St. Lucia. This 

 paucity of common species might, however, be expected, for these two 

 islands are separated from St. Vincent by very deep water, a depth of 

 1,346 fathoms separating the latter, and 1,000-2,000 the former, 

 indicative of a remote connection, if any, with St. Vincent. 



1 Cf. Bland, Proc. Amer. Philos. Soc. 1873, vol. xii, p. 58. 



