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Show 460 DR. F. B. WHITE ON T H E [May 7, For example, there is the one peculiar land-bird, AUgialites sanctee-helence, which is so closely allied to African species that it is, in all probability, a comparatively recent introduction. It seems rather remarkable that there are not more peculiar land-birds ; and the absence of Bats (none of which are recorded by Mr. Melliss) is another curious feature in the fauna of the island. There are also the species of West-Indian fish and marine Mollusca as well as the Indian-Ocean species of the same groups. Not very much can be made out of our present knowledge of these; but it seems to m e that no great obstacle exists to their introduction by means of the ocean currents. The present currents might have brought the southern and eastern species, while the reversal of the currents during a glacial period would bring the West-Indian and Brazilian animals. Though I have already invoked the agency of a reversed current for the purpose of bringing the Palaearctic fauna to the island, I think it is improbable that the arrival of the West- Indian fish at St. Helena was contemporaneous with that of the ancestors of the endemic fauna, though, in the case of some of them, it is quite possible. I would rather suppose that, since they are species of presumably later origin (or, should their origin be as remote as that of the endemic species, yet it was elsewhere than at St. Helena), they were brought to the island during a later (or a later part of the last) glacial period than the ancestors of the endemic species. There are also certain elements in the flora, viz. the five tropical weeds or sea-side plants of very wide distribution, which Sir. J. Hooker refers to. These are almost certainly of later introduction than the endemic and peculiar flora. Mr. Melliss remarks • of Entada scandens, L., that the large seeds " are cast ashore on the windward side of the island, having been brought from the Mauritius, or elsewhere, by sea-currents. They have been known to germinate ; but it is doubtful if one now exists there." This fact is suggestive of the origin of the five plants alluded to, as well as of some others thought by Mr. Melliss to be indigenous. Part II. DESCRIPTIVE. In his recent work upon St. Helena, Mr. Melliss was able to record the occurrence of only 8 species of Hemiptera. The names of only five species had apparently been determined ; and of these 4 were evident introductions. It was therefore left to Mr. Wollaston to add considerably to our knowledge of the St.-Helenian species of this order. The list which I now submit to the Society embraces the results of his six months' exploration of the island; and though it probably does not include all the native species, yet there is reason to suppose that the collection is a very representative one. A few months before his lamented death, Mr. Wollaston placed the collection in m y hands for determination, with directions that a 1 L. c p. 266. |