SCIENCE-ADVERTISEMENTS 



RECENT BOOKS 



Animal Communities in Temperate America, as Illustrated in the Chicago Region. By Victor 

 E. Shelford, Instructor in Zoology in the University of Chicago. 

 Thifl volume by Dr. Shelford presents the principles of field ecology, illustrated by the more widely distributed 

 animal habitats of the eastern half of temperate North America, and the aquatic habitats of a much larger territory. 

 Six chapters deal with general principles. 



In several chapters the animal communities of lakes, streams, swamps, forests, prairies, and various soils and topo- 

 graphic situations are considered from the point of view of modern dynamic ecology. A very valuable feature of the book 

 is the three hxmdred figures of widely distributed animals chosen to represent the chief types of animal communities 

 and their characteristic modes of life. 



380 paees, 8vo, cloth; price $3.00 (weight 44 oz.). 



Artificial Parthenogenesis and Fertilization. By Jacques Loeb, Head of the Department of 

 Experimental Biology, Rockefeller Institute for Medical Research. 



This new work presents the first -complete treatment of the subject of artificial parthenogenesis in English. Pro- 

 fessor Loeb published four years ago a book in German under the title Die chemische Entwicklungserregung des tieri- 

 schen Eies. Mr. W. O. E. King, of the University of Leeds, England, translated the book into English, and the trans- 

 lation has been revised, enlarged, and brought up to date by Professor Loeb. It gives, as the author says in the pre- 

 face, an account of the various methods by which unfertilized eggs can be caused to develop by physico-chemical 

 means, and the conclusions which can be drawn from them concerning the mechanism by which the spermatozoon in- 

 duces development. Since the problem of fertilization is intimately connected \vith so many different problems of physi- 

 ology and pathology, the bearing of the facts recorded and discussed in the book goes beyond the special problem 

 indicated by the title. 



318 pages, 12mo, cloth; price $2.50 (weight 36 oz.). 



THE UNIVERSITY OF CHICAGO PRESS ^,S?noi? 



AGENTS 

 The Baker & Taylor Company, New York. 



The Cambridge University Press, London and Edinburgh. 

 Karl W. Hiersemaim, Leipzig. 



The Maruzen-Kabushiki-Kaisha, Tokyo, Osaka, and Kyoto. 



Walker Prizes in Natural History 



By the provisions of the -will of the late Dr. William Johnson Walker two prizes are annually 

 offered by the Boston Society of Natukal Histoet for the best memoirs written in the English 

 language, on aubjeots proposed by a Committee appointed by the Council. 



For the beat memoir presented a prize of sixty dollars may be awarded; if, however, the memoir 

 be one of marked merit, the amount may be increased to one hundred dollars, at the discretion of the 

 Committee. 



For the next best memoir a prize not exceeding fifty dollars may be awarded. 



Prizes will not be awarded unless the memoirs presented are of adequate merit. 



The competition for these prizes is not restricted, but is open to all. 

 Attention is especially called to the following points : — 



1 . In all cases the memoirs are to be based on a considerable body of original and unpublished 

 work, accompanied by a general review of the literature of the subject. 



2. Anything in the memoir which shall furnish proof of the identity of the author shall be con- 

 sidered as debarring the essay from competition. 



3. Although the awards will be based on their intrinsic merits, preference may be given to 

 memoirs bearing evidence of having been prepared with special reference to competition for these 

 prizes. 



4. Each memoir must be accompanied by a sealed envelope enclosing the author's name and 

 superscribed with a motto corresponding to one borne by the manuscript, and must be in the hands 

 of the Secretary on or before April 1st of the year for which the prize is offered. 



5. The Society assumes no responsibility for publication of manuscripts submitted, and pubUoa- 

 tion should not be made before the Annual Meeting of the Society in May. 



Subjects for 1914 and 1915:— 



Any biological or geological subject. 



■^ ^ GLOVER M. ALLEN, 



Boston Society of Natural History, Secretary. 



Boston, Mass., U. S. A. 



