VOL. XL, NO. 479 NOVEMBER, 1906 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOUENAL 

 DEVOTED TO THE NATimAL SCIENCES 

 IN THEIK WIDEST SENSE 



CONTENTS 



I. Variation in the KTumber of Seeds of the Lotus . . DE. KAYMOND PEABL 757 

 n. TheCausesof Extinction of Mammalia . . . PROFESSOR H. F. OSBORN 767 



III. A Preliminary Study of the Finer Structure of Arc ell a 



J. A. CirSHMAN and W. P. HENDERSON 797 



IV. Notes and Literature: Astronomy and Physics, Willson's Laboratory 



Astronomy, Sabine's Laboratory Physics; Biology, Clements 's Research 

 Methods in Ecology, Moore's Universal Kinship; Zoology, Pratt's Verte- 

 brate Zoology, Stephens's California Mammals, Ichthyological Notes; 

 Botany, Clements on Leaf Structure, Wiesner on Light Intensity, 

 Bilancioni's Dictionary, Notes, The Journals . 803 



BOSTON, U. S. A, 

 GINN & COMPANY, PUBLISHERS 

 29 BEACON STREET 



