182 BOTANICAL GAZETTE [SEPTEMBER 
was made to the view which regards the pollen tube as the 
representative of the male prothallium. The recent discovery 
(in the author’s laboratory) of the occasional occurrence of a 
small lenticular cell, cut off before the usual divisions of the 
microspore nucleus, and also of the occasional direct division 
of the “vegetative” nucleus, suggest again the older homol- 
ogies. Comparison with the corresponding structures of 
heterosporous pteridophytes suggests that the occasional len- 
ticular cell cut off in the germinating pollen grain represents 
the “prothallial” cell which constantly appears in the former, 
and that the pollen grain as a whole, with the exception of this 
occasional cell, represents the single antheridium of the hetero- 
sporous pteridophytes. According to this view the ‘‘vegeta- 
tive” nucleus, with its cytoplasmic organization, represents the 
antheridium wall, from which the pollen tube is an outgrowth. 
The so-called ‘‘male cells’” would thus represent the sperma- 
tozoid mother cells of the heterosporous pteridophytes. 
In connection with the antipodal cells attention was called 
to the fact that they represent the most variable region of the 
embryo sac in dicotyledons, in which four types of antipodal 
development were noted: (1) a group of evanescent cells, 
usually three in number, characteristic of Amentifere and their 
allies; (2) three large antipodal cells, increasing in size with the 
sac, apparently very active, and usually becoming multinucleate, 
characteristic of Ranunculacee and their allies: (3) usually 
three comparatively permanent cells, not notable in size OF 
activity, rather common among Sympetale ; (4) an indefinite 
number of cells, forming a relatively permanent and very promi- 
nent tissue, often continuing its growth downward and breaking 
through the bottom of the sac, very characteristic of certain 
sections of the Composite. 
Freperic E. Crements: The transition region of the Caryo- 
phyllales. 30min. Presented by Cuares E. BESSEY. 
The history of the investigation of the transition region was 
discussed at considerable length. After a concise sketch of the 
histogenetic changes in the transition region in general, the 
