CONTENTS. 



I. The Variations and Mutations of the Introduced 

 Sparrow. Passer Domesticus. HERMON C. 

 BUMPUS i 



II. Cleavage and Differentiation. E. G. CONKLIN . 17 ' 



III. The Centrosomes of the Fertilized Egg of Allolo- 



bophora Foetida. KATHARINE FOOT ... 45 



IV. The Methods of Palaeontological Inquiry. W. B. 



SCOTT 59 



V. The Physiology of Excretion. ARNOLD GRAF . 79 

 VI. Some Neural Terms. BURT G. WILDER . . . 109 



VII. A Classification of the North American Taxaceae 

 and Coniferae on the Basis of the Stem Struc- 

 ture. D. P. PENHALLOW 175 



VIII. The Selection of Plant Types for the General 



Biology Course. JAMES ELLIS HUMPHREY . 193 



IX. The Rate of Cell-division and the Function of the 



Centres ome. A. D. MEAD 203 



X. Coalescence Experiments upon the Lepidoptera. 



HENRY E. CRAMPTON, JR 219 



XI. Some of the Functions and Features of a Biologi- 

 cal Station. C. O. WHITMAN 231 



