58 FAMILIES OF EARTHWORMS. [CH. I 



regard to the problems afforded by geographical distribu- 

 tion is the entire absence of any knowledge whatsoever 

 about extinct forms. We cannot therefore compare the 

 past with the present. 



Earthworms are divisible into seven families : — Crypto- 

 drilidse, Perichsetidse, Acanthodrilidss, Eudrilidse, Geo- 

 scolicidae, Moniligastridse, and Lumbricidse. Of these the 

 first three are very nearly related and may be united into 

 one super-family Megascolicidse, which possibly is really 

 equivalent to any of the other families Eudrilidse &c. 



The Cryptodrilidse are world-wide, but most abundant 

 in the Australian region and in South America. The 

 Perichsetidse are chiefly Australian and Oriental, but 

 occur in the Neotropical and Ethiopian regions. The 

 Acanthodrilidse are mainly massed in New Zealand, 

 South America, and Africa ; they are also found, though 

 rarely, in Australia, Malaya and North America. The 

 Eudrilidse are absolutely confined to Tropical Africa, 

 the Geoscolicidee to Tropical South America, Tropical and 

 Southern Africa, just reaching Europe and Malaya. The 

 Lumbricidse are probably only indigenous in the Nearctic 

 and Palsearctic regions. 



But it is necessary to go into further details to bring 

 out the salient facts in the distribution of the Oligochseta. 



The list, which I shall now give, is freed from obvious 

 importations like the Lumbricidse of exotic range dealt 

 with elsewhere. The same kind of argument removes 

 the Perichsetidse from the Nearctic and Palsearctic 

 regions. Two genera belonging respectively to the Geo- 

 scolicidse and Eudrilidse, viz. Pomtoscolex and Eudrilus are 



