CONTENTS OF VOLUME XXVII 



No. i. JULY, 1914. 



LOEB, LEO. The Correlation Between the Cyclic Changes in the 



Uterus and the Ovaries in the Guinea-pig I 



HOY, WILLIAM E., JR. A Preliminary Account of the Chromosomes in 



the Embryos of Anasa tristis and Diabrotica vittata 45 



ALLEE, W. C. The Ecological Importance of the Rheotactic Reaction 



of Stream Isopods 52 



No. 2. AUGUST, 1914. 



RICHARDS, A. The Effect of X-Rays on the Rate of Cell Division 



in the Eearly Cleavage of Planorbis 67 



WELCH, PAUL S. Habits of the Larva of Bellura Melanopyga Grote 



(Lepidoptera) 97 :' 



FASTEN, NATHAN. Fertilization in the Parasitic Copepod, Lernaz- 



opoda Edwardsii Olsson 115 



No. 3. SEPTEMBER, 1914. 



t^ ; ** 



ALLEN, WM. RAY. The Food and Feeding Habits of Freshwater 



Mussels 127 - 



GOODRICH, H. B. The Maturation Divisions in Ascaris incurva. . . . 147 



CHAMBERS, ROBERT, JR. Linkage of the Factor for Bifid Wing. The 



Bifid Wing and Other Sex-linked Factors in Drosophila 151 



EWING, H. E. Notes on the Regression in a Pure Line of Plant Lice 164 



No. 4. OCTOBER, 1914. 



HEWITT, J. H. Regeneration of Pleurotricha after Merotomy with 

 Reference Especially to the Number of Micronuclei and the Oc- 

 currence of Uninucleate Cells 169 



POWERS, EDWIN B. The Reactions of Crayfishes to Gradients of 



Dissolved Carbon Dioxide and Acetic and Hydrochloric Acids. . 177 



JUST, E. E. Breeding Habits of the Heteronereis Form of Platynereis 



megalops at Woods Hole, Mass 201 . 



CASE, E. C. On the Structure of the Inner Ear in Two Primitive 



Reptiles 213 



Hi 



