682 STUDIES IN GENERAL PHYSIOLOGY 
thenogenesis will ultimately make hybridizations possible 
which otherwise would be impossible. J intend to continue 
these experiments. 
VIII. PRELIMINARY EXPERIMENTS ON PHASCOLOSOMA, FUNDU- 
LUS, GONIONEMUS, AND PODARKE 
I will report briefly on experiments which I began but 
was not able to finish, partly from lack of material and partly 
from lack of time. My experiments on Phascolosoma were 
carried further than the rest. I began with putting the 
unfertilized eggs of this form in mixtures of 90 c.c. sea-water 
+10 c.c. 24n KCl and leaving them in this solution from 
thirty to one hundred and fifty minutes. I never saw an 
egg reach the two-cell stage. Then stronger solutions were 
tried, and now some of the eggs began to segment. When 
the eggs were put into a mixture of about 30 c.c. 24n KCl 
+70 c.c. sea-water for about thirty minutes, they reached 
a thirty- to sixty-cell stage. The appearance of the eggs 
was so good that possibly in a continuation of these experi- 
ments parthenogenetic larve will be produced. In these 
experiments I received valuable advice from Dr. Gerould of 
Dartmouth College, who is thoroughly familiar with the 
biology and embryology of this form. 
In Fundulus, a teleost fish, I succeeded in causing the 
unfertilized eggs to reach the two-cell stage, but lack of 
material prevented my carrying the experiments further. 
Inmy experiments on Gonionemus, a Medusa, I was assisted 
by Dr. Murbach, who was kind enough to select the females for 
me. Dr. Murbach had observed that by putting these animals 
into the dark they can at any time be caused to lay eggs. 
My attempts (four experiments) to cause artificial par- 
thenogenesis in these eggs have failed. All I was able to 
accomplish was to force the eggs to become amceboid and 
creep about, but no segmentation occurred. 
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