DIVISION AND MORPHOGENESIS 41 



the ecdysis-induced palintomy are of the trophontal type. 

 Thus, Synophrya enjoys two palintomic phases: one takes 

 place after growth in the molted exoskeleton and yields cili- 

 ates of the tomital structure. The other takes place after 

 growth in the blood of the crab and a long resting phase 

 and yields ciliates of the trophontal type. As far as visible 

 superficial structures are concerned, palintomy and hyper- 

 palintomy are identical. The difference lies in the post- 

 palintomic phase. Obviously the phenomena which follow 

 the last division are controlled by some metabolic process 

 which is itself controlled by the metabolism of the trophont. 



