224 BOTANICAL GAZETTE. [ September, 
sketch-book and drawing implements. The practical teach- 
ing of the ‘‘ preliminary men”’ is, on the whole, guide 
** Bower and Vines’ Practical Botany.’’ <A sufficient supply 
season is favorable. A collection of microscopical prepara- 
tions illustrating Bower and Vines’ book is kept in order to be, 
shown whenever a student, after several attempts, fails to 
get a sufficiently good preparation himself. The middle part 
of the room is occupied by two large tables, which serve for 
various purposes at different times and are very useful. 
Along the rear wall there is a bench with several sinks for 
most things necessary for a botanical laboratory. In conclu- 
sion I may mention that anybody interested in the construc: 
tion of a new laboratory will find much useful information 
a book by E. C. Robins, entitled, «‘ Technical School and Col- 
lege-Building.” (London, 1887. Whittaker & Co.) © 
Oxford, England. 
Zygomorphy and its causes, III. 
CHARLES ROBERTSON. 
When shallow gamopetalous flowers become horizontal, 
they are subject to the same conditions as polypetalous flow- 
ers, and, like them, are apt to become sternotribe. 
