/f) - 





MAY, 1912 



VOL. XXVI, No. 2 



TH E 



OTTAWA 

 N ATURA LIST 



Published by The Ottawa Field-Naturalists' Club. 



Editor: 



ARTHUR GIBSON, 

 Central Expbriubntal Farm. 

 OTTAWA. 



Hssociate JEDttotS: 



Harlan I. Smith, W. H. Harrington, P. A. Taverner, 



Anthropology. Entomology. Ornithology. 



W. T. Macoun, H. M. Ami, D.Sc. L. M. Lambe, F.G.S., 



Botany. Geology. Palaontology. 



Prof. John Macoun, M. A. Otto Klotz, LL.D. C. Gordon Hewitt, D.Sc, 



Conchology Meteorology. Zoology. 



CONTENTS: 



A Fossil Starfish with Ambulacral Covering Plates. By George 



H. Hudson - - - - 21 



Variation in Plant Life, its Biological Significance and Practical 



Value. Bv M. O. Malte - 26 



The Evolution of the Worlds. By J. S. Plaskett 29 



j 



Poison Ivy. By Charles Macnamara - - - - - - * 34 



j 



Book Notices: The Evolution of the Vertebrates and their Kin; 



A History of the Birds of Colorado ----- 37 



The Rolla L. Grain Co., Limited Ci ^JTrSTTNw <^.' 



ISSUED MAY 27, 1912 5J A j^^^, \\ ^ 



ftntertd at tht Ottawa Post Office as second class matter. . *~ (LI K A F 



4 m V* 



