The Classification and Distribution of Earthworms. 279 



the distribution of the group, except that many genera and 

 some species have a world-wide distribution. 



This is especially the case with the genera Lumhricus, 

 Allolohophora, and Perichmta} 



But it is necessary, in the first place, to clear the ground 

 by removing from the various faunal lists those species which 

 have been accidentally introduced by man's agency. This is 

 obviously not an easy task. The first question which arises 

 is, have we any right at all to suppose that this has been the 

 case ? I content myself with urging the general probability, 

 owing to the importation of plants from country to country, 

 and to mentioning one or two instances which are only 

 explicable on this theory. Some years ago the late Dr Baird, 

 of the British Museum, described in the Proceedings of the 

 Zoological Society a species of Perichceta {P. diffringens) 

 which had been sent to him from various parts of England, 

 but always from conservatories or from gardens for the adorn- 

 ment of which plants had been imported from abroad. 



In the Jardin des Plantes Perrier met with Perichceta 

 Houlleti, a species which has not been met with in any other 

 part of Europe. 



Both these cases (and others might be quoted) seem to 

 show that the species of Perichmta are in all probability not 

 indigenous, otherwise they would have been met with in 

 other places besides the immediate neighbourhood of plants 

 which had been recently imported from the countries of 

 which the species in question are certainly natives. 



Two examples which have come under my own observa- 

 tion may be mentioned as proving beyond a doubt (if indeed 

 there could be any doubt upon the point) that earthworms 

 may be carried from abroad to this country. 



^ With the exception of the doubtful case of Lumhricus and Allolobophora, 

 the following are the only species which are known to occur in more than one 

 region : — 



Urochoeta coretkrura. Neotropical and Oriental. 



Perichceta affinis. ,, ,, 



Perichceta Houlleti. ,, „ 



Perichceta indica. ,, ,, and Australian. 



Eudrilus decipiciis. Neotropical and Australian. 



