iv PREFACE. 



As in the earlier volumes, there will be found a list of 

 the principal losses to science by death, and a bibliography 

 of the more important publications, whether in the form 

 of books or of scientific memoirs. The latter, as hereto- 

 fore, has been prepared with the assistance of Professor 



Gill, of Washington. ^ ^ 



Spencer 1\ 13aird. 



Smithsonian Institution, Washington, March 1, 1878. 



