3/2 OLIGOCHAETA 



the presumably indigenous species are met with. This again 

 looks very like accidental transference. 



A mapping of the world in regions indicative of the dis- 

 tribution of earthworms produces a result which is slightly 

 different from the accepted division. North America. Europe, and 

 Northern Asia so far as is known agree in having as their 

 distinctive earthworms the family Lumbricidae, which is very 

 nearly the only one represented in these parts of the world. 

 The majority of the species are common to the two con- 

 tinents ; there cannot, in fact, be a separation of Nearctic and 

 Palaearctic ; we must accept the Holarctic region of Professor 

 Xewton. The Ethiopian region, on the other hand, is quite as it 

 is in other groups, being bounded to the north by the desert of 

 Sahara. The Neotropical region is quite distinct, and includes 

 Central as well as South America, and the West Indian islands, 

 even the Bermudas. It is, however, a question whether the more 

 southern portions of the continent should not be cut off from the 

 rest and joined with New Zealand, to form an Antarctic region. 

 In these two countries, and also in Kerguelen and Marion 

 Islands, the prevailing genera are Acanthodrilus and Microscolex. 

 In America Acanthodrilus is found nowhere but in the more 

 southern regions of the southern continent, as well as in the 

 Falklands and South Georgia. New Zealand is characterised by 

 other genera of Acanthodrilids besides Acanthodrilus itself ; but 

 the bulk of the species belong to the latter genus. Acanthodrilus 

 also occurs (three species only) in Queensland and at the Cape of 

 Good Hope. Microscolex is rather more widely dispersed, being 

 found in other parts of America and in Europe, the island of 

 Madeira (? accidentally imported); but it is undoubtedly chiefly 

 concentrated in South America and in New Zealand. Apart 

 from New Zealand, which, as already said, can only be doubtfully 

 referred to the Australian region, the latter appears to form one 

 with the Oriental region (to which, on account of its Perichae- 

 tidae, Japan should be added) of other writers. There is, so far 

 as earthworms are concerned, no " Wallace's line " at all. The 

 characteristic genera Perichaeta and Meyascolex range from one 

 extremity of the Indo-Australian region to the other. It is true 

 that Cryptodrilus and Megascolides are limited to Australia itself 

 (with the apparent exception of a species or two in America, for 

 I can hardly separate Argilophttus of Eisen from Mcyascolides} ; 



