118 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1956 



made necessary by the Federal Employees' Salary Increase Act of 

 1955, approved June 28, 1955. 



THE EXHIBITS 



Animals for exhibition are acquired by gift, deposit, purchase, ex- 

 change, birth, and hatching, and are removed by death, exchange, or 

 return of those on deposit. Although depositors are at liberty to 

 remove their specimens, many leave them permanently. 



As in any colony of living things, there is a steady turnover, and the 

 exhibits are constantly changing. Thus, the inventory of specimens 

 in the collection on June 30 of each year does not show all the kinds 

 of animals that were exhibited during the year, for sometimes 

 creatures of outstanding interest at the time they were shown are no 

 longer in the collection at the time the inventory is made. 



The United States National Museum is given first choice of all ani- 

 mals that die in the Zoo. If they are not desired for the Museum they 

 are then made available to other institutions or scientific workers. 

 Thus the value of the specimen continues long after it is dead. 



The two pairs of young giraffes and the pair of young gaurs, as well 

 as other animals brought to the Zoo in 1937 by the National Geographic 

 Society-Smithsonian Institution Expedition, have bred so successfully 

 that the Zoo has been able to dispose of surplus stock having a total 

 exchange value greater than the entire cost of the trip. Such animals 

 are exchanged with other zoos and with animal dealers for specimens 

 that are needed for this collection. 



ACCESSIONS 



The Zoo is particularly fortunate in having friends who show their 

 sincere interest by bringing in specimens or arranging for acquisitions 

 from foreign countries. 



To obtain suitable animals for exhibition extensive correspondence 

 throughout the world and a great number of personal contacts are 

 maintained. As a result it is frequently possible to obtain animals 

 that are not ordinarily available through animal dealers. Some of 

 these are gifts and some are obtained by purchase. 



OUTSTANDING ACQUISITIONS 



"Firsts" and rarities are always welcomed, and the Zoo acquired 

 a gratifying number of such specimens during the year. 



For the first time this Zoo has a pair of European bison, or wisents 

 (Bison bonasus), which are the European counterparts of the Amer- 

 ican bison. Wisents are extinct in the wild, but a few have survived 

 in captivity or in forest preserves in spite of wars in Europe. 



