421 



object in the ovarian egg. The yolk is in the form of small spheres em- 

 bedded in the protoplasm of the egg. In sixteen places near the circum- 

 ference there are large masses of protoplasm free from yolk spheres. 



--YOlK 



Fig. 1. Section through a segmenting egg of the 16-celled stage. Zeiss D 4 Oc. 



Cam. lucida. 



These are the blastomeres. No Nuclei were made out in them, but these 

 are very difficult to see in most of my preparations. The protoplasm of 

 the blastomeres is continuous with the general network between the 

 yolk spheres — in fact they form merely aggregations of it. The great 



CUTICLE 



YOLK 



'BLASTODERM. 



Fig. 2. After formation of the blastoderm. Zeiss D 4 Oc. Cam. lucida. 



quantity of yolk present has prevented nuclear division being followed 

 by cellular division. Two blastomeres are cut in the section figured. A 

 reconstruction of this egg showed that the blastomeres are approxi- 

 mately equally distributed all over the egg. They have nearly but not 



