CHAPTER VI 



THE EARTHWORM I NEREIS CHARACTERS OF THE PHYLUM 



ANNULATA 



THE general form and appearance of an earthworm are 

 familiar to everyone. In this country there are a number 

 of different species of earthworms belonging to several 

 genera, the commonest of which are Lumbricus and Allo- 

 lobophora but the differences between these are of minor 

 importance to the beginner, and any one of the common 

 forms will serve our purpose. 



Earthworms burrow into the soil and live on decaying 

 leaves and other organic matter, which they swallow to- 

 gether with a considerable quantity of earth. This earth, 

 mingled with the undigested portions of the food, is 

 passed from the body on to the surface of the ground in the 

 form of the well-known little heaps or " castings " which you 

 must have noticed in gardens and fields, especially after 

 rain, when the worms come more frequently to the surface. 

 In this way, a quantity of finely divided earth, mixed with 

 the faeces of the worms, is constantly being spread 

 out on the surface of the soil, and Darwin calculated 

 that on an average a layer of earth about one- 

 fifth inch in thickness, or about ten tons an acre, is thus 

 brought to the surface in the course of a year. Earth- 

 worms are therefore good friends to the gardener and 



