326 STUDIES IN GENERAL PHYSIOLOGY 
blastulee and reached the gastrula stage later than the larve 
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. 75 
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 
anegg with the extraovate # 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. 
75 shows a bursted egg in the twelve-cell stage. It can be 
seen that the micromeres form a bridge between the extrao- 
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