TABLE OF CONTENTS OF VOLUME XVIII, PART I. 
Page 
The Periodicity and Distribution of Radial Growth in Trees 
and their Relation to the Development of “Annual” 
Rings. J. G. Grossenbacher. 1 
Notes on Parasitic Fungi in Wisconsin— I. J. J. Davis. ... 78 
Notes on Parasitic Fungi in Wisconsin—II. J. J. Davis. . 93 
The Relation of the Corpus Christi Procession to the Corpus 
Christi Play in England. Merle Pierson . 110 
The Heat Budgets of American and European Lakes. With 
three Figures, and five Tables. Edward A. Biroe.. . 166 
Limnological Studies on Some Lakes in Central America. 
With four Figures and three Tables. Chancey Juday. 214 
Notes on Parasitic Fungi in Wisconsin—III. J. J. Davis 251 
Some Observations Concerning the Botanical Conditions on 
the Galapagos Islands. Alban Stewart .. 272 
