326 



STUDIES IN GENERAL PHYSIOLOGY 



blastulae and reached the gastrula stage later than the larvse 

 formed from entire eggs. In the most favorable case irregu- 

 lar precipitates of calcium salts were formed, but the changes 

 of form characteristic of the pluteus stage 

 did not occur. These monsters did not 

 develop beyond the spherical form of the 



FIG. 73 



FIG. To 



FIG. 74 



gastrula. They lived, however, as long as the normal 

 plutei, and, so far as motility was concerned, were comparable 

 to normal embryos. 



4. I will now enter upon these observations in somewhat 

 greater detail, and will use for this purpose a series of draw- 

 ings, all of which were made with the camera lucida at about 

 the same magnification, Fig. 73 gives the form of a normal 

 fertilized egg with its membrane. Fig. 74 gives the form of 

 an egg with the extraovate E which has burst in sea-water. I 

 have described, in a former paper, the first processes of 

 cleavage which occur in such an egg. We will now follow 

 the development of multiple embryos from such an egg. Fig. 

 7~> shows a bursted egg in the twelve-cell stage. It can be 

 seen that the micromeres form a bridge between the extrao- 



