CONTENTS. 



PAGE 



I. The Evoltitioti of the Sporophyte in the Higher 



Plants. Douglas Houghton Campbell . i 



II. The Nature of the Evidence exhibited by Fossil 

 Plants, and its Bearing upon 07ir Knowledge of 

 the History of Plant Life. D. P. Penhallow 19 



III. Influence of Inversions of Temperat?tre, Ascending 



and Descending Currents of Air, upon Distri- 

 bution. Prof. D. T. Macdougal ... 37 



IV. Significance of Myconliizas. Prof. D. T. Mac- 



dougal 49 



V. Instinct. Edward Thorndike 57 



VI. The Associative Processes in Animals. Edward 



Thorndike 69 



VII. The Behavior of Unicellular Oigajiisms. Her- 

 bert S. Jennings 93 



VIII. The Blind-FisJies. Carl H. Eigenmann . . . 113 

 IX. Some Governing Factors usually neglected in Bio- 

 logical Investigations. Alpheus Hyatt . 127 

 X. On the Development of Color in Moths and But- 

 terflies. Alfred Goldsborough Mayer . 157 



XI. The Physiology of Secretion. A.Mathews . . 165 

 XII. Regeneration: Old and Netv Interpretations. 



T. H. Morgan 185 



XIII. Nuclear Division in Protozoa. Gary N. Calkins 209 



XIV. The Significance of the Spiral Type of Cleavage 



and its Relation to the Process of Difleretitia- 



tion. C. M. Child 231 



XV. The Aims of the Quantitative Study of Variatioji. 



C. B. Davenport 267 



XVI. On the A^ature of the Process of Fertilization. 



Jacques Loeb 273 



111 



