FAUNA OF CEYLON. 9 



strictly Indo-Ceylonese genus (/.e., confined to Ceylon and the 

 Indian Peninsula), whose nearest relative is the genns Pare tropins 

 of Madagascar (Day, F., Fishes of India, 1878, p. 414). 



The Land Mollusca of Ceylon are highly peculiar, and the 

 largest of them are the species of the genus Acauiis, which is 

 confined to Ceylon, but exhibits close relationship with the genus 

 Helicophanta of Madagascar.* 



Tlie eurthwormsf of Ceylon include no fewer than thirty 

 endemic species, of which seventeen belong to the genus Mega- 

 scolex, whose headquarters are in Australia, while eight other 

 species of the same family {Megascolecidce) belong to genera 

 which, until recent years, had only been met with on the 

 Australian Continent, namely, the two genera Gryptodrilus and 

 Megascolides. One Ceylon species of Megascolex {M. armatus) 

 occurs also in Madagascar, Zanzibar, and several other localities, 

 though there is some doubt as to how far this species may have 

 been accidentally conveyed from place to place by shipping. 



The second family of Ceylon earthworms {MoniUgastridce) is 

 represented by four species of Moniligaster, which is a dominant 

 East Indian or Malayan genus. 



The Ceylon earthworms therefore afford an indication of the 

 existence of an Australian element in the fauna, which might be 

 further illustrated by examples taken from other groups of terres- 

 trial invertebrates. Thus, the snail Acavus appears, from the 

 large size of the Qgg and of the embryonic shell which forms 

 within it, to be as nearly related to the Australian genus Panda 

 as to the Mascarene genus Helicophanta (Cooke, op. cit.). 



The application of these facts to the theory of geographical 

 distribution can only be indicated here in the briefest manner. 

 The Island of Celebes is to the Oriental region what New Zealand 

 is to the Australian region. The Fauna of Celebes is one of the 

 most peculiar insular faunas in the world. Professor Semon has 

 voiced a widely held opinion that Celebes has received the most 

 characteristic members of its fauna, such forms as the monkey 

 (Cgnopithecus), the deer (^Anoa), the pig {Babirussa), the lemur 

 (Tarsius), &c., from the west, either from Asia or from a huge 

 continent or archipelago which spread far to the West, of which 

 Madagascar is perhaps the last remnant.| Of course Ceylon must 

 also have formed part of this continent, the Lanka of the ancients. 



' * Cooke, A. H. Molluscs. Cambridge Nafc. Hist., 1895, see pp. 303 and 355. 



The g-enus Acavi<s comprises the common Ceylon snails which are seen adhering 

 to the trunks of trees and to fences in most parts of the Island. 



t Michaelsen, W. Die Terricolenfauna Ceylons. Mt. Mus., Hamburg, XIV., 

 1897, 94 pp., 1 plate. 



I Semon. R. In the Australian Bush. Loudon, ISHil. 



c 25-03 



