268 Proceedings of the Royal Physical Society. 



earthworm fauna of Africa is very different indeed from 

 that of the warm parts of Europe or of Asia. It seems clear, 

 however, that although special soils are not required for the 

 existence of worms, they affect their numbers very considerably. 

 Naturally a soil which is rich, and productive of abundant 

 vegetation, will harbour more worms than one which is poor. 



It has been noticed by many that cultivation has a great 

 deal to do not only with the abundance but even the pre- 

 sence of worms in the soil at all. Certain districts of North 

 America have been stated to be entirely devoid of earthworms 

 until put under cultivation. 



Cultivation of the land has a very marked influence on the 

 abundance of the worms found in it. Mr Fletcher found ^ 

 that in the neighbourhood of Burrawang, N.S.W., the average 

 was 10,000 per acre in virgin soil. Urquhart^ gives 348,840 

 and 784,080 as the average in New Zealand districts which 

 had been seventeen years in grass ; and Mr W. W. Smith ^ 

 gives an estimate for cultivated lands of 5-16 per square foot. 



Before discussing some of the inferences which may be 

 drawn from a study of the distribution of this group of 

 worms, it is requisite to lay before the reader the facts. 



1 shall only mention those species which have been identi- 

 fied in a trustworthy manner, indicating others with a mark 

 of interrogation. The regions introduced by Mr Sclater will 

 be adopted, the precise habitat of the species being also 

 given, so far as is possible. Those which also occur in other 

 regions have the initial letter of that region appended, and 

 are printed in Clarendon type. In the case of genera occur- 

 ring in more than one region the generic name only is thus 

 distinguished, and only once for each region.* 



^ Notes on Australian Earthworms — Proc. Linn. See. N.S.W. (1886), 

 p. 527. 



2 On the Habits of Earthworms in New Zealand— Trans. N.Z. Inst., 

 vol. xvi. (1883), p. 269. 



^ Notes on New Zealand Earthworms — Trans. N.Z. Inst., vol. xix. 

 (1886), p. 133. 



•^ In the tables of species the term Pcrichccta is applied to all those species 

 which are included in the subgenera Pericliseta and Megascolex as defined by 

 myself (P. Z. S., 1890, pt. ii.). This is done for the sake of uniformity. It 

 would be impossible to apply the terms accurately in some cases. 



