480 PROCEEDINGS OF THE ACADEMY OF [1890 
4. The determination of the principal geological features of the 
Republic. 
Much of the zoological and botanical material obtained by the 
expedition is new either to science or to the Academy’s collection, 
and thus makes most valuable additions to the museum. The elabo¬ 
ration of this material has been confided to special investigators, 
whose reports (some of them already either printed or in prepara¬ 
tion) will appear in the Proceedings of the Academy, and in a final 
publication dealing with the explorations generally. 
The following papers have already been issued by the Academy: 
“ Birds collected in Yucatan and Southern Mexico.” By Wit- 
mer Stone. 
“ Barometric Observations among the High Volcanoes of Mexico, 
with a Consideration of the Culminating Point of the North Ameri¬ 
can Continent.” By Angelo Heilprin. 
“ The Corals and Coral Reefs of the Western Waters of the Gulf 
of Mexico.” By Angelo Heilprin. 
“ Echinoderms from the Northern Coast of Yucatan and the 
Harbor of Vera Cruz.” By J. E. Ives. 
“ The Geology and Paleontology of the Cretaceous Deposits of 
Mexico.” By Angelo Heilprin. 
“ Notes on a Collection of Shells from Southern Mexico.” By 
Frank C. Baker. 
Other papers now in course of preparation will appear during the 
early part of the year. 
Respectfully submitted, 
Angelo Heilprin. 
REPORT OF THE BIOLOGICAL AND MICROSCOPICAL 
SECTION. 
During the year 1890 this Section has held fifteen meetings. 
Dr. Samuel G. Dixon has been elected a member. 
Several papers of interest have been read at the joint sessions with 
the Academy, and interesting verbal communications have been 
made by Messrs. Sharp, Ryder, Rex, Wingate, Sudduth and others. 
The officers elected to serve for the ensuing year are as follows:— 
Director ,.Dr. Benjamin Sharp. 
Vice-Director, ..... John C. Wilson. 
Recorder, .Harold Wingate. 
