ARTIFICIAL PARTHENOGENESIS IN ANNELIDS 667 



exception of a few that had been in solution 2 and which 

 reached the trochophore stage. The eggs that remained 

 permanently in solutions 1 and 2 formed a large number of 

 swimming larvse. The eggs in solutions 3 and 4 were unde- 

 veloped and dead. 



Twenty-second series. It was evident that the addition 

 of 2 c.c. y^H HC1 to 100 c.c. sea-water was able to cause 

 the development of the unfertilized eggs of Chretopterus, 

 especially if the eggs remained permanently in this solution. 



1 intended to see how long the eggs must remain in such a 

 solution in order to reach the trochophore stage. Eggs 

 were put into such a solution and taken out in intervals of 

 ten, thirty, sixty, ninety, and one hundred and twenty min- 

 utes, respectively. One portion remained there permanently. 

 A large number of swimming larvre developed only in the 

 latter portion ; in the former there were none. The control 

 eggs remained absolutely undeveloped. 



Although these experiments are not yet finished, they 

 seem to indicate ^hat in a solution of 100 c.c. sea-water -f 



2 c.c. -J^n HC1 the unfertilized eggs of Chsetopterus can 

 reach the trochophore stage. 



V. MORPHOLOGICAL OBSERVATIONS ON THE DEVELOPMENT 

 OF THE UNFERTILIZED EGGS OF CH^TOPTERUS 



I have thus far confined myself to the statement that 

 certain solutions are capable of causing the unfertilized eggs 

 of Chsetopterus to reach the trochophore stage and swim 

 about. Nothing has been said as yet concerning the mode 

 of development of these parthenogenetic eggs. I have 

 watched their development very carefully and have made a 

 number of camera drawings. This part of the work is 

 essential for experiments on parthenogenesis. If one wishes 

 to be absolutely certain in regard to the parthenogenetic 

 character of the development, a close continuous observation 



