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Show 62 MR. GEOFFREY NEVILL ON THE [Jan. 28, plants, amongst the roots &c. of which they could easily have been brought. I have always noticed that the species having the supposed widest ranges are principally found close to the coast, or near some town, where, generally, the chief part of the vegetation has been introduced. In these places one rarely finds a species which can confidently be pronounced to be indigenous, about the only exception that I have met with being Gibbus mauritianus, which abounds everywhere in the sugar plantations near Port Louis. The commonest shell in the Mascarene Islands, as well as at Mahe and Praslin, is Helix similaris, which I believe has been thus introduced into all of them, either from India or Ceylon. At the great abundance of most of these species one cannot be surprised when one considers the vast numbers now to be found of Achatina panthera at Mauritius, and Achatina fulica at Calcutta, both of which have been introduced within the memory of many of the present inhabitants of those places. The others, of course, on account of their small size, have not been noticed, and consequently their introduction cannot be so easily traced. Tbe following are species which I believe, from the localities in which I found them, to have been introduced into the Seychelles :- Helix similaris, Ennea bicolor, Subulina clavulus, Carychium mauri-tianum, Acicula mauritiana, Succinea striata, and Achatina fulica. I should draw a very different deduction from the apparent affinities of the Seychelles Pubnonata to that which my friend and companion Mr. E. Newton, in his admirable paper in 'The Ibis' of 1867, arrived at from his careful study of the ornithology of these islands, where he states, "As regards the Ornis of the Seychelles, its Malagash tendency is evident." Now the land-shells seem to me to have far more affinity with the Indian fauna than with the Malagash or African. Perhaps it would be more correct to say that the Seychelles fauna forms an intermediate and connecting link between the two, rather approximating to the former than to the latter. Five genera are common to the Indian region which are not found in the Malagash, viz. Streptaxis, Cyathopoma, Onchidium, Helicina, and Paludomus, the reverse being the case with only two, Tropidophora and Gibbus. The only other species known of Stylodonta, as restricted, is from the Philippines (S. cepoides, Lea). The species oi Discus and Conulus are also common Indian forms. The only land-shells I can find recorded from the Seychelles which I did not myself meet with, are Helix militaris, Pfr., probably a variety of Stylodonta unidentata, and Bulimus ornatus^Dui., probably the species of which I have seen two specimens in the fine local collection of Mr. Caldwell, of Mauritius ; and if the same, it is a very handsome distinct species of the section Leptomerus, and must be extremely rare. 1. HELIX (DORCASIA) SIMILARIS, Fe'r. From Mahe and Praslin, where it abounds, but always near cultivated land, and never at any considerable height. The shells are |
