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carpogonial branch consists of four cells, and is 

 formed, near the apex of a growing shoot, from one 

 of the ordinary thallus cells. It curves backwards 

 towards its point of origin and adjoins the basal cell 

 from which the branch takes its rise. The tricho- 

 gyne is also bent outwards, and penetrating the 

 outer gelatinous coat of the thallus emerges into 

 the open. Simultaneously with the formation of 

 the carpogonial branch, the auxiliary cells are 

 formed in the following manner. Two cells adjoin- 

 ing the one which bears the carpogonial branch 

 each segment off externally one cell in such fashion 

 that the carpogonial branch lies between them. 

 The parent cells of these two auxiliary cells are 

 usually large thallus cells, but in no way distinct 

 from the ordinary thallus cells. Sometimes both, 

 sometimes one only is connected by a pore with the 

 cell which bears the carpogonial branch. Though 

 both of the auxiliary cells are apparently equally 

 adapted for its function, only one of them is utilised, 

 and it happens exceptionally that only one is 

 actually produced. In most cases the fertilised 

 carpogonium is directed towards the auxiliary cell 

 destined to be used, and the latter is then rich 

 . in contents. Immediately after fertilisation the 

 carpogonium fuses first with the cell of its branch 

 next it, and eventually with all four cells of the 

 carpogonial branch, while at the same time all 

 increase in size, as well as the cell which bears the 

 branch. The great cell arising by this fusion is 

 then farther increased by union with the cell that 

 bears it, and only one large nucleus is discernible for 



