1867.] senate—No. 52. 33 



Sent in Exchange. 



Chicago Academy, 45 species. 

 Copenhagen Museum, 194 species. 

 Haeckel, Prof. E. 61 species. 

 Keferstein, Dr. W. 65 species. 

 Shuman, Dr. B. S. 5 species. 



ACALEPHS. 



Dr. F. Muller. 4 species. Santa Catharina. 

 Thayer Expedition. 6 species. Rio de Janeiro. 



Report on the Department of Paleontology ', by N. S. Shaler. 



During the past year it lias been necessary for the Assistant 

 in this department to give a considerable portion of his time to 

 the work of caring for the collections recently received in the 

 Museum. This has reduced the time which could be given to 

 the task of carrying forward the genial arrangement of the 

 fossil collection, and the preparation of exchanges. Acting 

 under the general instructions of the Curator, a plan of opera- 

 tions in the arrangement of the fossils has been devised, an 

 outline of which may properly be included in this Report. 



The immediate object to be attained in this arrangement is 

 the division of the collection in such a manner that the speci- 

 mens may be most available for the prosecution of investiga- 

 tions, securing at the same time the amplest security against 

 the displacement of labels and the loss of other evidence bear- 

 ing on the history of the materials. The secondary objects are 

 the preparation of lists which will exhibit at a glance the 

 localities, formations and species represented in our collections 

 and guide the student to the spot where they are to be found, 

 together with other lists designed to show to our correspond- 

 ents the materials which we can furnish in exchange. 



In accordance with these objects it has been thought best to 

 institute three main lines of division in the specimens of each 

 class of the animal kingdom of which we have fossil remains, 

 dividing them according to their zoological classification, their 

 distribution in time or geological succession and their distribu- 

 tion in space or faunal limitation. In this division by the 

 5 



