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THE AMEBIC AN NATURALIST [Vol.XLVII 



that attached themselves to the board in June were doubt- 

 less statoblast colonies (although the shell of the stato- 

 blast was not found) as no embryos were seen until 

 July. None of the colonies formed statoblasts during 

 June, but began to form them early in July. At various 

 dates some of these elementary colonies were removed 

 from the board and the hooks of their statoblasts counted. 

 Later the separate colonies grew together and their 

 origin became confused, but it is certain that the sets of 

 statoblasts given in Table II are each derived from a 

 single statoblast-ancestor. All statoblasts that possessed 

 well-developed hooks were counted — there was no selec- 

 tion. 



TABLE II 



Distribution of Frequencies of Numbers of Hooks per Stag 



Our studies, though not made on one and the same 

 simple mass at successive periods, have been made on 

 several colonies early in the season (beginning July) and 

 at the end of the season (October). Counts on 241 stato- 

 blasts from 13 colonies made in July average 15.3 hooks; 

 7,255 statoblasts of one mass made in October gave an 

 average of 15.6 hooks; 5,593 statoblasts from a probably 



