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. 1 



It was to be expected that if KC1 makes the cells of the 

 same egg stick together, it might also cause several eggs to 

 agglutinate. We know, from the experiments of Driesch 2 

 and Morgan 3 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 Chaetopterus 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 Chretopterus 

 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 Chas- 

 topterus. Fig. 161 shows a number of trochophores which 

 originated from agglutinating fertilized eggs of Chastop- 

 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 HERBST, Arcniv filr EntwicTcelungsmechanik, Vol. IX (1900), p. 424. 



2 DRIESCH. il>i,L, Vol. X (1900), p. 411. 



3 MORGAN, ibid.. Vol. II (1895), p. 6.">. 



< ZUR STRASSEN, ibid.. Vol. VII (1898), p. 642. 



