50 



THE PHYSIOLOGY OF EARTHWORMS 



excretory picture of E. foetida after a period of starvation, both 

 bear the same relationship to one another although the actual 

 quantities involved are doubled. L. terrestris on the other hand 

 shows a trebled output of urea after inanition, but a slight drop in 

 the ammonia production. A. caliginosa, another small species, 

 shows a nitrogen excretion of similar pattern to L. terrestris 

 though it does not excrete such large quantities of urea or ammonia. 



Y3, .A 



Fig. 17. Excretion of urea N(x) amino +ammonia-N(o) and 

 amino + ammonia + urea-N (□) Lumbricus during transition from 



feeding to fasting ( ) and from fasting to feeding on elm leaf 



( ) in /Ltg/g body wt./day (from Needham, 1957). 



Fig. 17 shows the course of excretion over a period of days in 

 Lumbricus. 



Uric acid accounts for only a very small percentage (1-5%) of 

 the total nitrogen excreted in fed L. terrestris and a rather larger 

 proportion in E. foetida (34% in fed animals, 3-35% in starved 

 individuals). In this work no mention is made of allantoin. When 

 the posterior region of the animal is removed the excised portion 



