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 larve. 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. ~yn HCl to 100 c.c. sea-water was able to cause 
the development of the unfertilized eggs of Chetopterus, 
especially if the eggs remained permanently in this solution. 
I 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 larve 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 that in a solution of 100 c.c. sea-water + 
2 c.c. ~)n HCl the unfertilized eggs of Chetopterus can 
reach the trochophore stage. 
Vv. MORPHOLOGICAL OBSERVATIONS ON THE DEVELOPMENT 
OF THE UNFERTILIZED EGGS OF CHETOPTERUS 
I have thus far confined myself to the statement that 
certain solutions are capable of causing the unfertilized eggs 
of Chetopterus 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 
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