88 



A. J. GOLDFARB. 



The living clusters of embryos were easily distinguished from 

 the normal ones. The latter swam with a characteristic uni- 

 formly rotary motion at or near the surface of the water. Agglu- 

 tinated or fused blastulse swam at or near the bottom swaying 



53 



54 



FIGS. 50-54. 



irregularly and moving much more slowly. I have counted 

 as many as fourteen full-sized blastulse, of which Fig. 58 repre- 

 sents a large group of this kind. These are short lived, as 

 already mentioned, and only the smaller clusters continue their 

 development. 



THE DEVELOPMENT OF AGGLUTINATED AND FUSED GASTRUL^E. 

 The differentiation of the archenteron definitely established 

 the axes of the component members. Inasmuch as half eggs 

 developed in precisely the same manner as whole eggs, the follow- 

 ing statements apply to both. 



