140 ILLINOIS ACADEMY OF SCIENCE 



differentiated. Six chromosomes have been counted in the 

 dividing spermatogenous cells of Mnium and Polytrichum, 

 two common mosses, six is probably the number in Blasia and 

 Porella two of the liverworts, while three other liverworts, 

 Ricca, Marchantia and Fegatella have eight chromosomes 

 each. 



The androcyte, that is the cell destined to be transformed 

 into the sperm, whether it is triangular in outline as the result 

 of an oblique division or not, is constructed on the same general 

 plan as the androcyte mother-cell just described. We find a 

 definitely organized protoplast consisting of a nucleus and 

 cytoplasm, the latter bounded apparently by a very 

 delicate plasma membrane. Somewhat conflicting re- 

 ports have been made recently as to the nature of the pro- 

 cesses occuring as this androcyte becomes transformed into 

 the mature sperm. In addition to the presence of nucleus and 

 cytoplasm, there is quite general agreement as to the early 

 appearance somewhere within the cytoplasm of a conspicuous 

 dark staining body, the blepharoplast. The origin and nature 

 of this body is as yet a matter of dispute. Whether it functions 

 in the growth processes of the cilia or has to do with the change 

 in form of the androcyte, or possesses other entirely distinct 

 functions, it certainly forms the base of attachment of the 

 cilia. 



Briefly the transformation of the androcyte as the writer 

 has observed it in Mnium, one of the common mosses, is as 

 follows: (I find practically similar processes occurring in 

 Marchantia, Blasia, Porella and Fegatella.) The protoplast 

 of the androcyte rounds off slightly from the cell wall. The 

 blepharoplast appears in the cytoplasm near the plasma mem- 

 brane apparently as a cytoplasmic differentiation in the andro- 

 cyte in which it is to function. The blepharoplast grows as a 

 more or less radially flattened band in a course closely applied 

 to the plasma membrane. The nucleus becomes closely ap- 

 plied to the blepharoplast, the chromatin network and nucle- 

 olus, if the latter is present, changing meanwhile in structure 

 so that eventually the entire nucleus stains quite homogen- 

 eously. The nucleus lengthens parallel with and becomes more 

 and more closely applied to the blepharoplast, so that the two 

 form first a crescent and then a coil of one or two turns. The 



