VIII] MOVEMENT AND MIGRATION 127 



aid of living carriers such as birds ? It has been 

 definitely shown that these creatures actually do 

 convey such small animals as Mollusca attached to 

 their feet. Is anything of the kind likely in the case 

 of earthworms? In the first place it may be safely 

 asserted that if it be possible it has not been actually 

 proved. This however might be perhaps put down to 

 the lack of sufficient observation of actual birds and 

 the contents of such masses of soil as are found 

 attached to their feet. A consideration of the habits 

 of earthworms seems to imply that such a mode of 

 transference from country to country is unlikely. In 

 the first place we remark that the general behaviour 

 of earthworms renders this unlikely. Even the 

 smaller kinds, whose bulk would allow of their being 

 carried, are too active in their habits to permit of a 

 safe transference. When disturbed they wriggle and 

 progress with activity. It is not conceivable that 

 they would remain quiescent for sufficient time to 

 allow of a long voyage. But while the bodily trans- 

 ference of adult earthworms seems highly improbable 

 it is conceivable at the first view that their cocoons 

 might be so transferred. We require to know rather 

 more about the cocoons of earthworms before we can 

 accept this view as a possibility ; as far as our present 

 knowledge goes it is not likely that these animals can 

 be assisted to emigrate in this way. 



For the cocoons are rather bulky for this kind of 



