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Show 456 DR. F. B. WHITE ON THE [May 7, island. Most of these genera, in addition to being Miocene and of very wide distribution, are characteristic Palaearctic genera at the present time. Amongst the peculiar genera many have their affinities (and, hence, probable ancestry) with Palaearctic genera; while in the North-Atlantic islands there seems to m e to be more evidence of alliance with St. Helena than Mr. Wollaston was inclined to admit. Mr. Murray (whose line of migration, in part, at least, coincides, as will have been noticed, with mine-he arguing, however, for continuity of land) was decidedly in favour of affinity with the North-Atlantic islands; and his knowledge of Coleoptera was, it must be allowed, so extensive as to require his opinion to be received with attention. It is true that since he wrote on the subject our knowledge of the St.-Helenian Coleoptera has been immensely increased; but so far as I can see, nothing has been found to invalidate (but rather to increase) the argument in favour of such alliance. Taking Mr. Murray's abstract1 of the Coleoptera of the North- Atlantic islands, we have in Madeira 266 endemic species against 120 aboriginal European species, the endemic species being all akin to European forms. Then in the Canaries we find that, out of a total of 930, 224 species are identical with Madeiran, the peculiar characters of the Madeiran fauna being there in force. Next come the Cape-Verd Islands, of which M r . Wollaston says, " O u r recent explorations in the Cape-Verdes have shown their coleopterous population to be so far more than I had anticipated on the Canarian and Madeiran type, that I a m any thing but certain that it would not be more natural to regard the whole of these Atlantic islands as characterized hy a single fauna unmistakably the same, even whilst necessarily differing as to many of its exact details (and through the fact of mere distance) in the more widely separated groups." In fact we find in the three archipelagos just what might have been expected. As we move southwards the same general character of the fauna is found to be present, but the particulars gradually alter. And this, it seems to me, is apparent even when St. Helena is reached. Making due allowance for its remoteness and different latitude, the character of the fauna is the same, though the details are very considerably altered. For example, in Madeira we have the Heteromerous genera Hadrus and Hegeter, with 3 and 1 species respectively ; in the Canaries Hadrus has vanished, but Hegeter has no less than 19 species; in the Cape-Verds Hegeter has almost disappeared, having but a single species, but its place has been taken by a new genus, Oxycara, with 10 species ; in St. Helena all these genera have vanished, but are represented by two new and allied genera-Hadrodes and Tarphiophasis, regarding the first of which Mr. Wollaston remarks that it has a good deal in common with the Madeiran Hadrus. Tarphiophasis too seems evidently a development of Hadrodes, just as the latter is of Hadrus. Then, again, M r. "Wollaston remarks of the St.-Helenian Opatrum hadroides that it is closely allied to species from the Cape-Verd, Canarian, and Madeiran archipelagos, and is even more akin to one, and probably 1 L. c. p. 12 4c. |