PAPERS ON BOTANY 139 



cell of the plant body. When near maturity each antheridium 

 consists of a more or less globular mass of cubical cells, sur- 

 rounded by a wall layer and united with the main body of the 

 plant by a relatively short thick stalk. In the majority of the 

 liverworts, at least, if not also in the mosses, the protoplast of 

 each cubical cell gives rise by oblique division to two cells which 

 when viewed from one side present a triangular outline. The 

 two triangular protoplasts, Allen of Wisconsin has termed an- 

 drocytes. Each androcyte becomes transformed into a sperm. 

 Hence two sperms are eventually developed from each of the 

 cubical cells. The occurrence of the last division in an oblique 

 plane seems at least not so constant and prominent in the 

 mosses as in the liverworts. 



The protoplast, or organized protoplasm of one of these 

 cubical cells, consists of a nucleus and cytoplasm. The outer 

 boundary of the cytoplasm next to the cell wall forms a very 

 delicate membrane, the plasma membrane. The remainder of 

 the cytoplasm is more or less finely granular or lumpy when 

 fixed and stained. Allen, however, finds in one of the mosses, 

 Polytrichum, a certain part of the cytoplasm, the kinoplasm, 

 organized into definite granular plates or membranes. The 

 individual granules of the plates he calls kinetosomes. These 

 kinoplasmic plates are present in the resting stage of the cell 

 and seem to actively function in spindle formation as the cell 

 prepares to divide. 



The nucleus of this cubical cell, or androcyte mother cell, 

 is spherical and sharply delimited by a distinct membrane, the 

 nuclear membrane. The most prominent content of the nu- 

 cleus is chromatin material variously arranged. Either a 

 very distinct densely staining nucleolus may be present with 

 surrounding chromatin granules in a more or less clearly de- 

 fined, often sparse net work, or the chromatic material may be 

 almost entirely included in one densely staining central nu- 

 cleolar like mass. It seems quite evident that during a certain 

 prophase of division whether a distinct nucleolus may be ob- 

 served or not, the chromatin becomes largely collected into a 

 mass in the center of the nuclear cavity. This mass, some- 

 times presenting an irregular, sometimes a smooth outline, 

 is resolved into a more or less closely wound or irregularly 

 gathered spireme. From this spireme the chromosomes are 



