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CONTENTS 
PAGE 
Genetic Factors Affecting the Strength of Linkage in Drosophila 
By A. H. Sturtevant 555 
Changeable Coloration in Brachytjra ByW.H, Longley 609 
The Means of Locomotion in Planarians By Caroline E. Stringer 691 
[GENERAL BIOLOGY 
Application of the Laws of Action, Reaction and Interaction in Life Evo- 
lution By Henry Fairfield Oshorn 7 
Temperature Optima for Human Energy By Ellsworth Huntington 127 
GENETICS 
The Use of Vasectomized Male Mice as Indicators By C.C. Little 186 
Body Pigmentation and Egg Production in the Fowl 
By J. Arthur Harris, A. F. Blakeslee and D. E. Warner 237 
The Bearing of Selection Experiments with Drosophila upon the Frequency 
OF Germinal Changes By Edwin Carleton MacDowell 291 
Dominance of Linked Factors as a Means of Accounting for Heterosis 
By Donald F. Jones 310 
Hybrids of Zea Tunic ata and Zea Ramosa By G. N. Collins 345 
On Utilizing the Facts of Juvenile Promise and Family History in Awarding 
Naval Commissions to Untried Men By C. B. Davenport 404 
Inter-Periodic Correlation in the Egg Production of the Domestic Fowl 
By J. Arthur Harris, A. F. Blakeslee, and Wm. F. Kirkpatrick 565 
On the Growth and Fecundity of Alcoholized Rats 
By E. C. MacDowell and E. M. Vicari 577 
An Oenothera-Like Case in Drosophila By Hermann J. Muller 619 
Incompatibility of Mutant Races in Drosophila. . ^3; C. W. Metz and C. B. Bridges 673 
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 
PHYSIOLOGY AND PATHOLOGY 
The Rate of Discharge of Central Neurones 
By Alexander Forbes and W. C. Rappleye 12 
A Physiological Study of Noctiluca, with Special Reference to Light Produc- 
tion, Anaesthesia and Specific Gravity By Ethel Browne Harvey 15 
On the Composition of the Medusa, Cassiopea Xamachana and the Changes in 
It after Starvation ByS. Hatai 22 
The Production in Dogs of a Pathological Condition Which Closely Resem- 
bles Human Pellagra By Russell H. Chittenden and Frank P. Underhill 195 
The Transformation of Pseudoglobulin into Euglobulin By William N. Berg 261 
Chemically Induced Crowngalls By Erwin F. Smith 312 
Fertility and Age in the Domestic Fowl By Raymond Pearl 354 
What Determines the Duration of Life in Metazoa? 
By Jacques Loeb and J. H. Northrop 382 
The Interrelation between Diet and Body Condition and the Energy Produc- 
tion DURING Mechanical Work in the Dog 
By R. J. Anderson and Graham Lusk 386 
