equal cells, four of which 

 other four divide. Then 

 small ones at one pole : 



108 cell stages. 



Now in the groat majo 

 the cleavage results in tl 



The time taken for the ha 



Though in the majority 

 halfblastulas formed fron 



half-egg formed a symmeti 



cells must he one-half the normal. Wl 



furnish a complete individual, both rigl 

 rior, dorsal and ventral parts, and had 

 to the other egg-half. 



Of the 30 perfect blastulas only 15 I 

 often the case with normally formed 1: 

 the morning of the third day active ii 

 individuals. They then take on the pi 

 are formed and the normal course is fc 

 normal, but small, plutei were raised. 



If each half-egg may thus form a con 

 of forming twins by partial separation < 



the experiments above recorded thougl 

 observed amongst the many examined 

 probability that the partial separation 



especially noticeable as it shows that f 

 stage there resulted an apparently no 



