KOFOID AND RIGDEN: SCHIZOGONY IN GONYAULAX. 347 



which the schizonts are united in their polar regions with but slight 

 constriction separating the successive members of the series. There 

 is no evidence of skeletal fission but the chain is thecate. The entire 

 theca, except in polar regions of contact, is found in initial stages of 

 formation on the distal members of the series. A progressive reduc- 

 tion in size passes from the central to the distal members. Fission 

 thus appears to progress most rapidly in distal parts of the chain and to 

 be followed by the formation of the theca upon exposed parts of the 

 cell body. 



Anterior schizonts are smaller than the posterior ones suggesting 

 the effect of the direction of locomotion. 



Levander's Peridinium catenatum belongs rather to the genus 

 Gonyaulax. Its schizonts are uniform in size. Skeletal fission in the 

 formation of chains occurs in this species. 



