168 “BOTANICAL GAZETTE [SEPTEMBER 
early stages of siphonogamy, with which spermatozoid habit was 
more or less associated. 
8. The pollination of gymnosperms is but a continuation of 
the ordinary method of dispersing aerial spores employed by 
cryptogams, the chief result of the retention of the megaspore 
upon the male gametophyte being the development of siphonog- 
amy. 
THE UNIVERSITY OF CHICAGO. 
