TABLE OF CONTENTS. 



PAGE. 



Letter of Transmittal 3 



Table of Contents 5 



Officers of the Academy 7 



Members of the Academy 9 



Proceedings of the Sixteenth Annual Session 13 



Presidential Address, by A. A. Veblen 21 



Some Improved Laboratory Devices and Apparatus, by A. A. Veblen 34 



A Study in the Hereditary Transmission of Finger Patterns, by A. A. Veblen 44 



Factors of Extinction, by Herbert Osborn . 47 



Forestry in Iowa, by B. Shimek — 53 



Analyses of Certain Clays used for Making Paving Brick for Cedar Rapids, by C. O. Bates 61 



The Sanitary Analyses of Some Iowa Deep Well Waters, J. B. Weems 63 



The Chemical Composition of Sewage of the Iowa State College Sewage Plant, by J. B. 



Weems, J. C. Brown and E. C. Myers . 70 



Menke's Method of Preparing Hvponitrite-s, by Alfred N . Cook 82 



Calcium Carbide as a Dehydrating Agent for Alcohols, by Alfred N. Cook and Arthur 



L.Haines 86 



The Sioux City Water Supply, by Alfred N. Cook and C. F. Eberly .... 90 



Igneous Bocks of the Central Caucasus, and the Work of Loewinson-Lessing, by 



Charles R. Keyes 101 



Evidences of Recent Uprisings of the Shores of the Black Sea, by Charles R. Keyes 103 



A Devonian Hiatus in the Continental Interior — Its Character and Depositional Equiv- 

 alents, by Charles R. Keyes 105 



Paroxymetamethylacetophenone and Some of Its Derivatives, by J. Q. Goodwin 113 



On the Occ irrence of Rhizopods in the Pella Beds in Iowa, by J. A. Udden. 120 



Pleuroptjrx in Iowa Coal Measures, by J. A. Udden 121 



The University of Montana Biological Station, by Maurice Ricker 122 



A Large Red Hydra, by Maurice Ricker 125 



Some New Double Bromides and Their Dissociation in Aqueous Solution, by Nicholas 



Knight 127 



The Vasciilar Cryptogams of Iowa and the Adjoining Parts of Southeastern Minnesota 



and Western Wisconsin, by L. H. Pammel and Charlotte M. King 134 



Preliminary Notes on the Flora of Western Iowa, Especially from the Physiographical 



Ecological Standpoint, by L. H. Pammel, 152 



A Ruling Engine for Making Zone Plates, by W. M. Boehm . 181 



A List of Plants Collected in Lee County, Florida, by A. S. Hitchcock 189 



Ustiloginae of Iowa, by H. H. Hume 226 



