CONTENTS 
Page 
Genetics. — ^Incompatibility of Mutant Races in Drosophtla . 
By C. W. Meiz and C. B. Bridges 67$ 
Astronomy. — ^Absorption Effects in the Spiral Nebulae.. By Heber D. Curtis 678 
Botany. — ^The Synergetic Action of Electrolytes . , By Or an L, Raber 682 
Psychology. — ^Appetites and Aversions as Constituents of Instincts .... 
By Wallace Craig 685 
Botany. — ^Rapid Respiration after Death . , . . . • • By A. R. C. Haas 688 
Zoology. — The Means of Locomotion in Planarians . . By Caroline E. Stringer 691 
Oceanography. — ^Diurnal Changes in the Sea at Tortugas, Florida . . . 
By J. F, McClendon 692 
Physics. — ^Note on Interfereometer Methods of Measuring the Elastics of 
Small Bodies By Carl Bar us 693 
Geography. — Sublacustrine Glacial Erosion in Montana . « ByW. M. Davis 696 
Physiology. — ^The Effect of Stretching on the Rate of Conduction in the 
Neuro-Muscular Network in Cassiopea By J. F. McClendon 703 
Genetics. — ^A Criticism of the Evidence for the Mutation Theory of De Vries 
from the Behavior of Species of Oenothera in Crosses and in Selfed Lines 
By Bradley Moore Davis 704 
Chemistry. — ^The Spectra of Isotopes and the Vibration of Electrons in the 
Atom By William D. Harkins_and Lester Aronherg 710 
Physiology. — The Effect of Oxygen Tension on the Metabolism of Cassiopea 
By J. F. McClendon 715 
National Research Council, Scientific Publications from Germany . . . 717 
, Report of the Geology and Paleontology Committee 721 
, First Report of Committee on Zoology 724 
, The Scope and Work of the Botanical Raw Products Committee , 731 
, Meetings of the Executive Committee . . . . 733 
List of Publications of the National Academy of Sciences 743 
Report of the Autumn Meeting 753 
Index • . • « • .««..•......... 759 
