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Show 18G9.] ON T H E L A N D - S H E L L S O E T H E S E Y C H E L L E S . 61 The animal of Melampus parvulus (Nutt.) agrees with the above in all respects excepting its tentacles, which are shorter and more stout in proportion. I will take this opportunity of correcting an error in the habitat of Melampus pusillus (Gm.). It does not occur at the Sandwich Islands. The above observations show that Dr. Gray's opinion, that the shells are not always a guide to the generic relations of the animal, is correct. 2. Additional Notes on the Land-Shells of the Seychelles Islands. By G E O F F R E Y N E V I L L , C.M.Z.S. The land-shells of the Seychelles are not only remarkably few in number, but are also, generally speaking, local. This probably arises from the nearly complete destruction at some period or another of the original flora; for at Mahe, and at most of the other islands we visited, it was only on the extreme summit of one of the highest passes in the former, and on the top of the mountain at Silhouette, that I could perceive anything like a peculiar or ancient flora. Praslin, it is true, has a vast number of the Coco-de-mer trees and many shrubs, some of which may possibly prove peculiar and of interest to the botanist; but vegetation seems to thrive little better under them than under the ordinary Cocoa-nut or Vacoa Palm. It seemed to me evident that the flora at Mahe must originally have been very different. Large fires have probably been the chief cause of the destruction; and the cutting down the timber, whether for firewood or to plant Cocoa-nuts, must also have had considerable effect, and have enabled the Pine-apple, Cinnamon, Bamboo, & c , and even possibly some of the common Mauritian ferns (Gleichenia &c.) to obtain a firm footing. These introduced plants now cover large tracts of country, killing all the more delicate indigenous flowers and ferns. The first mentioned, more especially, is abundant in most of the islands, and grows almost up to the tops of the highest mountains. Where the large timber has been thus destroyed, the water, almost as soon as it falls, forms for itself channels, and, running off from the soil, causes it in a short time to become dry and more or less arid. This is clearly perceptible both at Mauritius and Bourbon. In such situations there are no shells to be found, excepting, indeed, some two or three species, such as Achatina fulica &c. By searching, however, where the trees have been recently cut down, one finds quantities of dead shells, evidently killed by want of moisture and by exposure to the tropical sun. Out of the meagre list of the land-shells I found at the Seychelles, I believe a considerable number to have been introduced. It does not appear difficult to account for this when one considers that such has been the case with a large number of the commonest trees and |