gametangia of the Phaeophyeeae. The writer has 

 cussed this problem in a paper on ''The Origin of 

 Archegonium, " G and advanced the view that the arche- 

 gonium and antheridiiun arose from some type of pi 

 locular sporangium or gametangium through the differ 

 entiation, in response to terrestrial life habits, of a sterile 

 protective envelope around the gametes. Schenck 

 contribution "Ueber die Phylogenie der Archegoniaten 

 und der Characeen" 7 accepts the above view and even 

 argues for a direct descent of the archegoniates from 

 the Ph;pophyrea\ carrying the speculation far beyond 

 point with which the writer is in agreement. A di: 

 sion of the difficulties which face Schenck 's hypoth 

 would, however, lie outside of the province of this paper. 



Assuming that the sporophyte is normally character 

 ized by mitoses concerned with the diploid number of 

 chromosomes, the results of the recent research 

 Chlorophycea 1 make it appear probable that none of the 

 known living types present an alternation of generations 

 even in its simplest form. The striking differences be- 

 tween the Chlorophycea? and the simplest archegoniates 



che- 



fer- 

 >rile 



become : 



the latest re- 



rch. 



that 



Passing to the Plup 

 cytological conditions 

 complicated than any 

 phycese. Only the specialist 

 appreciate the diversity of the 

 ment in the large assemblage c 

 algae. The chief groups ex 

 among themselves than do the 

 green algne. Unfortunately ou 

 ogy of reproduction in the Pha> 

 groups, the Dictyotales, Fucah 



-S; ; r; 



re to 



known for the Chloro- 

 long the alga? can fully 

 pes and lines of develop- 

 forms termed the brown 

 bit greater differences 

 ivergent lines among the 



lir, 



