676 STUDIES IN GENERAL PHYSIOLOGY 
ions influences the degree of agglutination in the cleavage 
cells. Herbst has observed that in sea-water without Ca the 
cleavage cells of fertilized eggs show a tendency to fall 
apart.’ 
It was to be expected that if KCl makes the cells of the 
same egg stick together, it might also cause several eggs to 
agglutinate. We know, from the experiments of Driesch?’ 
and Morgan’® on the eggs of sea-urchins and of Zur Strassen‘ 
on the eggs of Ascaris, that if two eggs stick together they 
may give rise to a single embryo of larger dimensions. I 
have never observed giant embryos in the parthenogenetic 
eggs of sea-urchins. But I have seen them in almost every 
experiment in which the Chetopterus eggs had been treated 
with potassium. In such cases often two or more eggs would 
stick together, and the result was either two or more trocho- 
phores grown together or a single giant embryo of twice or 
three times the mass of a normal trochophore. Of course 
there were all kinds of transitions between the two extremes. 
The formation of one giant embryo through the fusion of 
two or more eggs is the more remarkable as the Chetopterus 
eggs possess a membrane even in the unfertilized condition. 
This membrane is evidently liquefied at the point of contact 
of two eggs. This agglutination caused by K is not only 
noticeable in unfertilized but also in fertilized eggs of Che- 
topterus. Fig. 161 shows a number of trochophores which 
originated from agglutinating fertilized eggs of Chetop- 
terus. All these and many other specimens of this kind 
were found in a few drops of the culture taken out with a 
pipette. I have tried to make camera drawings of the 
various types that occurred. The embryos were eight hours 
old, and began to move. No. 1 (Fig. 161) is a trochophore 
1 Hersst, Archiv fiir Entwickelungsmechanik, Vol. IX (1900), p. 424, 
2 Driescu, ibid., Vol. X (1900), p. 411. 
3 MorGAN, ibid., Vol. II (1895), p. 65. 
4ZuR StRAssEn, ibid., Vol. VII (1898), p. 642. 
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