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Show 738 GEOGRAPHICAL DISTBIBUTION OF EARTHWORMS. [Dec. 5, ORIENTAL REGION.-Perichceta, Megascolex, Perionyx, Typhosus. A U S T R A L I A N REGION.-Megascolex, Biporochceta, Acanthodrilus, Bigaster, Cryptodrilus, Megascolides. N E O T R O P I C A L REGION.-Anteus, Rhinodrilus, Urobenus, Pontoscolex, Biachceta, Ocnerodrilus, Kerria, Acanthodrilus, Perichceta. E T H I O P I A N REGION.-Microchceta, Kyiwtus, Siphonogaster, Gordiodrilus, Pygmceodrilus, Benhamia, and Eudrilidae. It is clear from this abbreviated list that the Ethiopian and Neotropical regions are the richest in abundant peculiar genera ; that there is the closest resemblance between the Nearctic and the Palae-arctic regions ; that there is a less close resemblance between the Oriental and the Australian regions, in that both are characterized especially by Perichcetidce and Gryptodrilidce; but it appears to me that the Australian region of Mr. Sclater does not express the facts of the distribution of Earthworms. N e w Zealand is so different. There w e have Acanthodrilidae (belonging to four genera) forming the characteristic fauna and a very few Gryptodrilidce and Perichcetidce', in Australia, on the other hand, w e have the two families Gryptodrilidce andPerichcetidae extremely abundant and varied and the merest trace of the family Acanthodrilidae (three species only). The Earthworm-fauna of N e w Zealand in fact is less like that of the Australian continent than it is like Patagonia and some of the intervening islands; from Patagonia, the Falkland Islands, Kerguelen and Marion Islands the only Earthworms that are known belong to the genus Acanthodrilus. The amount of information on this subject is not large, but it can hardly be an accidental circumstance that the four or five collections of worms examined from these different parts of the world should have consisted only of members of the genus Acanthodrilus', it must at least indicate that that genus is the prevalent form. I should therefore propose an Antarctic region to comprehend the tract of continent and islands just mentioned. With this exception and possibly with the exception of the Nearctic and Palsearctic, which ought perhaps, from the point of view of Earthworms, to be fused into one circumpolar region, I think that the facts in the distribution of the Earthworms confirm the justice of, distinguishing the rest of M r . Sclater's regions, viz. Oriental, Neotropical, and Ethiopian. North of the Sahara the Earthworms, so far as we know them, belong to European genera. I should not, however, in every case make the boundaries of these regions along exactly the same lines as those usually adopted. Japan, for example, which possesses a good many Perichcetidce, ought, I believe, to be referred to the Oriental region: perhaps the Australian region should be limited to the continent of Australia; such worms as I have seen from Borneo conform to the Oriental rather than to the Australian type. On various points of this kind information is greatly wanted; it is an easy thing to collect these animals, and they can be readily preserved by killing them in very weak spirit and then preserving them in strong spirit, which should be changed once or twice. |
