46 EARTHWORMS AND THEIR ALLIES [ch. 



terrestrial members of the same genus are trifling, 

 further information may prove that this case is on 

 all fours with that of Eiseniella referred to above. 

 There are plenty of similar instances which I shall 

 not enumerate. 



We may now therefore pass on to the second 

 category. These examples are obviously much more 

 important because they are of worms which appear 

 to be wholly aquatic, or very nearly so, and which 

 belong to definite genera easily distinguishable as 

 such from their allies. The examples are not how- 

 ever very numerous. And they belong practically 

 exclusively to the family Geoscolecidae, a family 

 which, it will be seen later, is confined to South 

 America, South Africa, Madagascar, certain parts of 

 India and Burmah and of Europe. It is not a family 

 which has reached the greater part of the East or 

 which has been carried to the Antarctic parts of the 

 globe. It is furthermore very important to bear in 

 mind that there are reasons for regarding this family 

 Geoscolecidae as one of the more modern branches of 

 the Oligochaeta ; this latter statement tends to prove 

 that the aquatic life is, as already suggested, a 

 secondary matter in these worms, and is not due to 

 their belonging to an ancient race which has never 

 left the waters of the land. 



A very interesting fact ofifers itself first of all in con- 

 sidering this family of earthworms. The Geoscolecidae 



