DISTRIBUTION OF THE TERRICOLOUS OLIGOCHAETES 



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Usually, the species of Lumbricidae have a very wide distribution and 

 therefore the Palearctic earthworm fauna is very uniform. For example, the 

 earthworms of Afghanistan (cf. Omodeo, 1959) belong to species, all but one of 

 which are found also in Italy; most of the Manchurian earthworms belong to 

 species that we find in Caucasia as well as in the Urals; etc. Therefore, all 

 premises exist for considering the North American populations of European 

 earthworm taxa an integral part of the Holarctic, ancient fauna. 





Fig. 14. Distribution of Luinbriciis festivus and L. terrestris. 



In addition to indirect proofs and merely inductive arguments, there exist 

 also very convincing direct proofs: Allolobopliora caliginosa, a very common 

 earthworm throughout the Palearctic, is represented in the United States by 

 two types, molita and anwldi (Gates, 1952), which have already evolved to a 

 subspecific or maybe even specific rank. We also have the case of the North 

 American genus Sparganophilus, represented in England and France by an 

 endemic species. Finally we have, scattered all over the arc from the Faeroes 

 over Iceland to Greenland, a large number of stations of Euro-American 

 species. The biometric and caryological studies of the populations of Iceland 

 and Greenland permit us to state that they are not as similar as would be 

 expected had they developed recently from introduced material. Instead, 



