INDEX 
A 
Abel, Arthur R., Intensive Ornithological Survey of Typical Square 
Mile of Cultivated Prairie 385 
Academies, State, Information on 14 
Acuity in Hearing, Normal Curve of, Paul B. Anderson.. 229 
Agricultural Geology, Content of, John E. Smith 175 
Airplane Loop, Photographic Determination of Form of, and Dyn- 
amics of, L- P. Sieg 207 
Alaska Fungi, J. P. Anderson 99 
Algebraic Surfaces, Taxonomy of, R. P. Baker 197 
American Association, Affiliation with 15 
Amphibian Muscle, Relative Position of Maxima Contractions of, 
when Subjected to Various Ranges in Temperature, R. L. Parker. . . 311 
Anderson, J. P., Some Alaska Fungi 99 
Anderson, Paul B., Normal Curve of Acuity in Hearing 229 
Anteoninse, Study of Phylogeny of, F. A. Fenton 337 
Aorta, Branches of, and Subclavian Artery of Rabbit, F. M. Baldwin. 301 
Arapahoe National Forest, and Rocky Mountain National Park, Some 
Plants of, L. H. Pammel and R. I. Cratty 51 
Arey, M. F., Address of, at Calvin Memorial 29 
Army Worms and Variegated Cutworms, Recent Outbreak of, in 
Iowa, H. E. Jaques 343 
Audiometer, Iowa Pitch Range, C. C. Bunch 230 
B 
Baker, R. P., Taxonomy of Algebraic Surfaces 197 
Bakke, A. L., See Yocum and Bakke, also Rudnick and Bakke. 
Baldwin, Francis Marsh, Notes on Branches of Aorta and Subclavian 
Artery of Rabbit 301 
Baldwin, Francis Marsh, Susceptible and Resistant Phases of Dividing 
Sea-Urchin Egg 287 
Bee Plants, Midsummer, in Mississippi Zone, Clayton County, Ada 
Hayden 109 
Binaural Phase Difference and Intensity Effects, Frequency Limit of, 
G. W. Stewart 218 
Binaural Phase Difference not Caused by Intensity Effect, Perception 
of, G. W. Stewart 217 
Biocolloids, See Corn Stalk Tissue. 
Bird Records of Past Two Winters, 1918-1920, in Upper Missouri Val- 
ley, T. C. Stephens 395 
Bird Records of Season of 1919-1920 in Vicinity of Iowa City, Dayton 
Stoner 379 
Bird Survey, See Prairie. 
Blackening Curve of Photographic Plate, Characteristic, On Finding 
the Equation of, P. S. Helmick 223 
