DEVELOPMENT OF NEPHRIDIA OF PHERETIMA 57 



(March to June) out of doors in moist places in the surface 

 layers of the soil in abundance, but during the rains (July 

 and August) they were very rare. My friend Mr. B. K. Das 

 has since informed me from Allahabad that he has been able 

 to collect cocoons of earthworms (not necessarily of Phere- 

 tima) in the months of November, December, January, and 

 February ; and he rightly suspects that egg-laying continues 

 almost throughout the year. Of course the number of cocoons 

 found in the winter months is very small, since the surface 

 layers of the soil get very dry on account of the prolonged 

 drought, and the worms go deep into the soil and are them- 

 selves difficult to obtain. 



As regards the cocoons of P. rodricensis,i my observa- 

 tions are based on worms kept in captivity in garden -pots in 

 a hot-house. In order to make sure of the specific identity of 

 my cocoons I kept worms of this species in sterilized earth, 

 to which decaying leaves previously sterilized were added from 

 time to time. From a number of garden-pots containing 

 these worms I could obtain cocoons in any number containing 

 embryos at various stages of development throughout the 

 year. The statement is usually made in text-books that 

 ' egg-capsules are formed in spring or early summer and 

 the young worms grow mainly during the summer months. 

 Sometimes large clusters matted together may be found in 

 autumn packed away under clods or in banks where there is 

 a favourable condition of moisture '.^ Wilson (18) says, 

 ' egg-laying seems in special cases to continue throughout the 

 year, though it is most active in the spring and summer 

 months. I have found the capsules of Lumbricus 

 foetidus out of doors in nearly every month of the year, 

 but in mid-winter they are only found in decomposing compost- 

 heaps where the temperature is maintained at a tolerably high 

 point '. From these authorities and from my own observations 

 I am inclined to believe that the time of egg-laying depends 



1 I am indebted to Col. J. .Stephenson of the University of Edinburgh 

 for identification of this species. 



2 Osborn, ' Economic Zoology ', New York, 1908, pp. 110-11. 



