154 OLIGOCHAETA 



I leave this question, however, undecided. It does, however, appear to be clear that 

 the Australian region can have, as regards earthworms, no existence. To begin with, 

 New Zealand is essentially different from Australia. The prevalent forms in Australia 

 are Perichaetidae and Cryptodrilidae ; the most abundant worms of New Zealand are 

 Acanthodrilidae. There are a few species of the two former families in New Zealand 

 and three species of Acanthodrilus in Australia. The Australian continent shows, 

 in fact, far closer resemblances to the Oriental region. In both the Cryptodrilidae 

 and Perichaetidae are the prevailing forms. But the genera of the Oriental region 

 are for the most part different, or, if identical, are more or less abundant than in 

 Australia. Thus Perichaeta is the dominant Perichaetid in India and Malaya, and 

 Megascolex in Australia, though both genera occur in both regions. As regards the 

 Cryptodrilidae there are (with the doubtful exception of Cryptodrilus) no genera in 

 common. I do not in fact propose to merge the Australian and Oriental regions ; 

 but rather to dwell upon the resemblances in order to accentuate the differences 

 between Australia and New Zealand. The latter islands do not, however, stand 

 sufficiently alone to warrant the introduction of a special region (as was proposed 

 by Mr. Huxley for other reasons). The characteristic earthworms of New Zealand 

 are Acanthodrilidae — four genera, of which three are peculiar, and two of which 

 (Deinodrilus and Plagiochaeta) are very weU marked; but the same family (the 

 genus Acantkodrilus only) is equally characteristic of Patagonia and the adjacent 

 islands. The only earthworms known from Marion and Kerguelen islands are also 

 Acantkodrilus. These facts seem to me to be sufficiently important to require the 

 ■formation of an Antarctic region, circumpolar in extent. I am not inclined to put 

 the Cape part of Africa in this region. Though Acanthodrilids occur there these 

 are also abundant throughout tropical Africa. It seems very possible that a former 

 greater extension northwards of the Antarctic continent may account for those 

 Acanthodrilids; but the equally great or greater prevalence of Geoscolicids, and 

 especially of Eudrilids, distinguish undoubtedly the Ethiopian region. 



The facts at present known about the distribution of earthworms lead me to 

 divide the world into the following regions : — 



(i) Palaearctic (excluding Japan, but including Africa N. of Sahara); 



(2) Nearctic ; 



(3) Oriental ; 



(4) Australian (the continent of Australia only ?) ; 



(5) Antarctic (New Zealand^ islands of Antarctic ocean, Patagonia) ; 



(6) Ethiopian ; 



(7) Neotropical (including Central America and West Indies). 



