ARTIFICIAL PRODUCTION OF NORMAL LARV.E 611 



of the irregular morula stage is preserved. This is intel- 

 ligible if we remember that the blastula originates through 

 the cleavage cells moving or sticking to the periphery of the 

 egg. The other blastulse represented only smaller pieces of 

 a single egg. In some cases one part of the egg disintegrated 

 and formed debris at- 

 tached to the other part 

 which reached the blas- 

 tula stage (5, 6, and 7). 

 Each one of these blas- 

 tul was moving and 

 had to be immobilized 

 to make the camera draw- 

 ing. It is impossible to 

 give a fair idea of the 

 variety of forms of blas- 

 tulse one sees in such ex- 

 periments. No egg of 

 this lot (solution 1) 

 reached the pluteus 

 stage. All died the 

 second day. The eggs 

 that had been in solu- 

 tion 2 (equal parts of 

 2 ^wMgCl 2 and sea- water) looked very different from the 

 preceding lot (Fig. 150). After twenty-four hours many 

 of them had developed into blastulas. These blastulas left 

 no doubt that they came from eggs without a membrane, in- 

 asmuch as in the majority of cases several blastulse originated 

 from one egg. Quadruplets were especially frequent (Fig 

 150, iv and v), but twins and triplets were also quite com- 

 mon. I watched their development, and am thus quite cer- 

 tain that these multiple embryos sticking together came from 

 one egg. The feature that distinguished these embryos 



FIG. 150 



