CONTENTS. 



PAGE 



I. The Structure of Protoplasm, E. B. WILSON . . i 



II. Cell-Lineage and Ancestral Reminiscence. E. B. 



WILSON 21 



III. Adaptation in Cleavage. F. R. LILLIE . . . . 43 



IV. Protoplasmic Movement as a Factor of Differen- 



tiation. E. G. CONKLIN 69 



V. Equal and Unequal Cleavage in Annelids. A. L. 



TREADWELL 93 v^ 



VI. The Cell Origin of the Prototroch. A. D. MEAD . 113 



VII. Relation of tlic Axis of tJic Embryo to tJie First 



Cleavage Plane. C. M. CLAPP 139 



VIII. Observations on Various Nncleolar Structures of 



the Cell. T. H. MONTGOMERY, JR 153 



IX. Protoplasmic Contractility and Phosphorescence. 



S. WATASE 177 



X. Some Problems of Regeneration. T. H. MORGAN 193 



XL The Elimination of the Unfit as Illustrated by 

 the Introduced Sparrow, Passer Domesticus. 

 H. C. BUMPUS 209 



XII. On the Heredity of tJie Marking in Fish Embryos. 



JACQUES LOEB 227 



XIII. Do the Reactions of Lower Animals Due to Injury 



Indicate Pain-Sensations? W. W. NORMAN . 235 



XIV. North American Ruminant-Like Mammals. W. B. 



SCOTT 243 



XV. Caspar Fricdrich Wolff and the Thcoria Gene- 



rationis. W. M. WHEELER 265 



XVI. Animal Behavior. C. O. WHITMAN ...'.. 285 



