666 STUDIES IN GENERAL PHYSIOLOGY 
Twentieth series.—The following solutions were used: 
(1) 100 c.c. sea-water + 2 cc. ay” NaHO 
(2) 100 eee, “ KHO 
(3) 96 “ 44  4n Na,CO,; 
(4) 100 “ 49 syn HCl 
(5) 100 “ 48 “« 
(6) Normal sea-water (control) 
The eggs of one female were distributed in these solu- 
tions. One portion of the eggs was taken out of these solu- 
tions and put back into normal sea-water ; the others remained 
permanently in these solutions. Twenty-four hours later 
the results appeared to be as follows: Of the eggs that had 
remained in the solutions for twenty-four hours, those in 
solutions 2 and 4 had well-developed trochophores that swam 
about. In solution 1 several eggs seemed to have developed, 
but I was unable to find one swimming or with cilia. Those 
in the other solutions were undeveloped. The eggs that had 
been in solutions 2 and 4 for only five to ten minutes had a 
few trochophores; the others were undeveloped. 
It is evident that KHO is more effective than NaHO, and 
it is natural that the effect of the K ions should have been 
added to the effect of the HO ions. But the fact is very 
striking that the addition of a small amount of HCl to the 
sea-water caused the parthenogenetic development of the 
Cheetopterus eggs. 
Twenty-first series.—The unfertilized eggs of a Cheetop- 
terus were distributed in the following solutions: 
(1) 100 c.c. sea-water +1 cc. dyn HCl 
(2) 100 . +2 vo ote 
(3) 100 « 43 «os 
(4) Normal sea-water (control) 
One portion of eggs remained in the solutions five minutes, 
the others permanently. The eggs that were taken from the 
solutions after five minutes were undeveloped, with the 
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