REPORT OF ASSISTANT SECRETARY. 38 



The ttooi'ing over of the south east raiig-e, already mentioned, made it 

 possible to extend the laboratory of the Division of Plants. New dust- 

 tight cases were built for the herbarium and placed in the second story 

 of the rang'e, whicli they occupy jointly with the mammal collections of 

 the Department of Agriculture. A row of skylights in the roof over 

 these cases gives abundance of light. 



The work of reorganizing the exhibition series of birds in the main 

 hall of the Smithsonian building, which was begun last year, has been 

 completed, except in so far as regards labeling. The old wooden floor 

 in this hall was replaced by one of stone and cement (terrazzo) at the 

 beginning of the year and a plan was adopted for lighting the center 

 of the hall, formerly almost totally dark, by artificial means. New 

 cases with large glass were provided for the four spaces about the 

 entrance, styled "the quadrangle,'' and in them have been placed spe- 

 cial exhibits of birds of more than ordinary interest, such as the birds 

 of paradise, parrots, hornbills, etc. The cases are lighted l)y incan- 

 descent electric lamps, provided with hoods and reflectors. The result 

 of these changes is that this section of the hall, formerly unflt for 

 exhibition -purposes, is now one of the most attractive points in the 

 building. The reduction in the number of birds exhibited has relieved 

 the congested condition of the cases, and makes it possible to view each 

 specimen satisfactorily. The cases themselves are old and not as free 

 from dust as could be wished, but otherwise the improvement efl'ected 

 may be considered to have amply repaid the labor involved. A con- 

 siderable amount of relabeling remains to be done, and better provision 

 made for the bird groups and the collections of eggs and nests. 



A series of enlarged illustrations of Rotifers was added to the new 

 exhibition series of lower invertebrates during the year. In the 

 North American series the groups remaining to be represented are 

 the parasitic and nonparasitic worms and the polyzoa and certain of 

 the Crustacea. 



No opportunity was found during the year to reorganize the exhib- 

 its of insects and of plants, and no important changes were made in 

 the exhibition series of moUusks. The osteological exhibit, as stated 

 in a previous report, is as full as can be accommodated in the present 

 quarters. 



EXPLORATIONS. 



The extensive collecting operations of Dr. W. L. Abbott, who gen- 

 erously donates the fruit of his labors to the ^Tuseum, continued 

 during the year. 



The activities of the scientiflc bureaus of the Government, involv- 

 ing the acquisition of natural history specimens, vary from year to 

 year. During the past year, as in many years preceding, the opera- 

 tions of the United States Fish Commission resulted in large additions 

 to the Museum. 



NAT MUS 1900 8 



