104 EARTHWORMS AND THEIR ALLIES [ch. 



Geoscolecidae, the fact that there are more peregrine 

 Megascolecidae will lose some of its importance. 

 With the Lumbricidae the case seems to me to be 

 different. Here the preponderance, not only in species 

 (relatively speaking) but in individuals, is much above 

 that of other families. This preponderance I should 

 be disposed to assign to the newness of the family 

 coupled with the vigour seen in new races. That 

 this is a possible explanation is borne out by 

 the fact that the 'Perichaetidae' {i.e. the genus 

 Pheretima) is the most salient race of peregrine 

 Megascolecidae, and it is now generally held that 

 this group is the most modern of that enormous 

 family. 



Another general statement may be made with 

 even more confidence, viz. that it appears to be an 

 undoubted fact that some species are more capable 

 of extending themselves than others. Thus Eudrilus 

 eugeniae occurs everywhere on the great land masses 

 of the globe, except in Europe ; it is in fact circum- 

 mundane in the tropical zone, as is also Poutoscolex. 

 Dichogaster holavi is again a trifle more restricted 

 in its range, having been recorded from tropical 

 Africa, South America, West Indies, Madagascar, and 

 India. Its occurrence near Hamburg in Europe is 

 also to be noted. A little more restricted still is 

 Nematogenia pmiamaensis whose range is in Central 

 America, tropical West Africa, and Ceylon. Lastly 



