63 



r.ot rotate as readily v/hile br-inf{ cut avart, i.ggs v/ere di- 

 vided during different sta?;es of cleavage from tv.-o lo six 

 hours old. They were then olaced under conditions as near- 

 ly like those under which the eggs noo divided developed as 

 possible. Jniortunately , as these experinients were inci- 

 dental and inccirplete, no eggs were divided during the 

 two-cell stage and their cleavage followed in detail, 

 So;:.e eggs that were laid between five and six in the if^orn- 

 ing were divided at 10,46 A« ii, iiore than one half of the 

 frag.T-ents continued Lo cevelon and by six o'clocl: in the 

 evening had reached the free-swimiting stage. They were re- 

 tarded a little in their development; whole eggs usually 

 arrive at this stage at about four to four-thirty. They 

 were slightly smaller than einbryos frori whole eggs, but 

 annarently lust as active and norir^al. except in size. By 

 the next -corning .hey had reached Lhe elongated planula 

 stage and were in good condition, swirrr.ing at the surface 

 of the water. 



