96 EARTHWORMS AND THEIR ALLIES [oh. 



CHAPTER VI 



PEREGRINE FORMS 



Dr Michaelsen has used this term to describe 

 those species which possess some powers of migration 

 over the sea, denied to the majority of worms, and 

 probably due to the direct interference of man. Thus 

 we find in collections of earthworms from various 

 parts of the world not only examples of forms which 

 do not come from other parts of the world, but also 

 a few which occur in many or even most of such 

 collections. It is for example to be actually expected 

 that a collection of earthworms made in South America, 

 the Philippine Islands, or Australia will contain ex- 

 amples of the apparently ubiquitous Pontoscolex 

 corethrurus. This is what has actually happened in 

 cases of which I have personal knowledge, as well as 

 in many others recorded in the literature of the 

 subject. I have myself received this worm from the 

 three parts of the world mentioned, and also from 

 Hawaii. Others have increased its known range to 

 other parts of the South American continent, to 

 Central America, the West Indies, the islands of 

 Sumatra, Java, Borneo, Celebes, Mauritius, and 

 Madagascar, etc. It is in fact found everywhere in 



