BAUSCH & LOMB 



T Dissecting Microscopes 



For botany classes, the most practical and moder- 

 ate-priced good microscope obtainable. The body is 

 of wood, shaped to form hand rests ; the lenses are 

 achromatic doublets, mirror extra large, hinged tray 

 at bottom for lenses and dissecting instruments. 



List Price, $3.50. Special discount to schools. 



Write for special prices on dissecting sets of all kinds, 

 chemical glassware, chemicals, microscopes, etc. 



Bausch & Lomb Opt. Co. 



Rochester, N. Y. 



New York, Boston, Washington, Chicago, 

 & San Francisco, Frankforta/m Germany § 



NOT LOWEST IN PRICE- 



CHEAPEST, 



BECAUSE BEST AND GOES FARTHEST. 



GROCERS EVERYWHERE. 



WALKER PRIZ ES IN NATU RAL HISTORY! 



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

 Boston Society of Natural History for the best memoirs written in the English language, on subjects pro- 

 posed by a Committee appointed by the Council. 



For the best 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 In all cases the memoirs are to be based on a considerable body of original and unpublished work, accom- 

 panied 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 considered as debar- 

 ring the essay from competition. v 



3. Preference will be given to memoirs showing intrinsic evidence of being based upon researches made directly 

 in competition for the 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. 

 Subjects for 1906 : — 



1. An experimental field study in ecology. 



2. A contribution to a knowledge of the nature of competition in plants. 



3. A physiological life history of a single species of plant. 



4. Phylogeny of a group of fossil organisms. 



5. A study in stratigraphy. 



6. A research in mineral physics. 



7. A study of entectics in rock magmas. 



8. A study in river capture. 

 Subjects for 1907. 



1. The structure and affinities of some fossil plant or group of fossil plants. 



2. The development of the gametophytes in any little known representative of the Coniferales. 



3. The anatomy and development of some order or group of the angiosperms. 



4. The functions and habits of animals in their relations to environment and to each other. 



5. The habits and structure of any species of the Myriapoda. 



6. A contribution to a knowledge of the rate of speed at which birds travel. 



Boston Society of Natural History, GLOVER M. ALLEN, 



Boston, Mass., U. S. A. Secretary. 



