SCIENCE.— AB VERTISEMENIS. 



Walker Prizes in Natural History. 



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

 offered by the Boston Society oe Natural History for the best memoirs written in the English 

 language on subjects proposed 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 dis- 

 cretion 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 unpub- 

 lished 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 

 considered as debarring the essay from competition. 



3. 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 ist of 'the year for which the prize is offered. 



Subjects for 1S96 : — 



(i) A study of an area of schistose or foliated rocks in the eastern United States. 



(2) A study of the development of river valleys in some considerable area of folded or faulted 

 Appalachian structure in Pennsylvania, Virginia or Tennessee. 



(3) An experimental study of the effects of close-fertilization in the case of some plant of 

 short cycle. 



(4) Contributions to our knowledge of the general morphology or the general physiology of 

 any animal, except man. 



Subjects for 1897 : 



(i) A study of glacial, fluviatile, or lacustrine phenomena associated with the closing stages 

 of the glacial period. 



(2) Original investigations in regard to the chalazal impregnation of any North American 

 species of Angiosperms. 



(3) An experimental investigation in cytology. 



(4) A contribution to our knowledge of the morphology of the Bacteria. 



SAMUEL HENSHAW, 



Secretary. 

 Boston Society of Natural History, 



Boston, Mass., U. S. A. 



