FURTHER NOTES ON THE COCOONS OF ALLOLO- 



BOPHORA FCETIDA. 



KATHARINE FOOT AND ELLA CHURCH STROBELL, 

 WOODS HOLL, MASS. 



The fact that cocoons of Alloloboplwra are formed during copu- 

 lation challenges the interpretation that spermatozoa are stored 

 in the spermatheca; in order to produce cross fertilization. We 

 found, however, such conclusive evidence that the spermatozoa of 

 the cocoon are derived from the spermathecae, that this apparent 

 inconsistency was stated in an earlier paper as a problem for further 

 investigation. 1 



During the summer of 1901, we were able to make at least 

 one step in this direction. We found that cocoons can be formed 

 and deposited when the worms are not copulating. Isolated 

 worms deposited cocoons for weeks, as many as ten cocoons 

 being laid by one worm without copulation. 



The method of experimenting was as follows : Single worms 

 with a pronounced clitellum were isolated in half-pint bowls, each 

 bowl being half filled with compost in which the worms had been 

 found. Immediately after this compost was collected, it was 

 carefully sifted to get rid of even the smallest worms, and it was 

 then kept for three or more days before using. This was done 

 to allow any cocoon already in the compost to reach a stage of 

 development that would make it impossible to mistake it for a 

 cocoon laid by the worm isolated for the experiment. At the end 

 of three days the isolated worm was put in a bowl of fresh com- 

 post and the compost in which the worm had been kept was_sifted 

 under running w r ater through a sieve with meshes too fine to allow 

 a cocoon to pass. By this process nearly all the earth was washed 

 away, and any cocoons present, were easily secured. 



A perfectly fresh cocoon, i. e., one with a slime-tube, was 

 often found, but more often the cocoons contained eggs in a later 



1 The Cocoons and Eggs of Allolobophora fxtida, Jour. Morph., Vol. XIV. , No. 3, 

 1898, pp. 496, 497. 



