306 The American Naturalist. [April 



maturation of the egg cell and the antherozoids that corres 

 pond to polar globules in the animal egg ? In short, it i 

 thought that we find analogous exudations of nuclear matte 

 almost universally in plants. In the development of the 

 planogametes of Ulothrix a portion of waste protoplasm b. 

 traded with the planogametes containing probably the 

 truded nuclear matter. 



Among the well differentiated female gametes, it, is said, Per- 

 onospora affords an excellent illustration of what we may term 

 polar globules. In the development of the oosphere, accord- 

 ing to Wagner, the numerous nuclei which at first are scattered 

 uniformly throughout the oogonium (fig. 57) at length ap- 

 proach the periphery leaving the central portion of the oogon- . 

 ium occupied by large vacuoles, and a email central mass of 

 protoplasm connected with the periphery by protoplasmic 

 strands. The nuclei now limited to the periphery further 

 divide and 2 or 3 (?) finally leave the periphery and approach 

 the central mass of protoplasm traveling along the connecting 

 protoplasmic strands and supposedly unite in the centre, 

 forming the nucleus of the oosphere (fig. 58). While these 

 nuclei are thus traveling toward the centre, the cell wall 

 of the oosphere begins to form, separating the central mass of 

 protoplasm with its two nuclei from the peripheral or peri- 

 plasm with' its numerous nuclei, some of which are supposed 

 to be used up in the formation of the oosphere wall. The 

 nuclei thus relegated to the periplasm have been considered as 

 of the nature of polar globules. But with the present light on 

 the subject it must remain surely as a very doubtful and 



In the development of the antherozooids of ferns, when the 

 antherozooid is set free there is attached to its posterior end 

 an appendage which is usually described as a protoplasmic 

 vesicle, but Dodel-Port and Belajeff think it to contain nuclear 

 matter also from the mother cells. 



In flowering plants the nucleus of the pollen divides 

 into two cells (figs. 39 and 40) a vegetative and a gen- 

 erative. The vegetative is thought by Strasburger to have 

 the function of a polar globule. Again the generative 



