these cabinets contain a selected series of the nests and eggs, for 

 exhibition. Owing to the rapid injury of eggs by exposure to 

 light, the greater part of the collection is stored in the drawers of 

 the cabinets, in order to preserve them from more or less rapid 

 deterioration.* 



In addition to the birds on exhibition in the Bird Hall, the 

 Museum has a Study Collection, consisting of unmounted skins, 

 stored in the Curator's rooms on the Fifth Floor. In extent and 

 value it is the second in importance in America. It numbers about 

 30,000 specimens, selected with special reference to their scientific 

 value, authoritatively determined, and including many hundred 

 original types. It forms a reserve collection for scientific research 

 and for the use of specialists. The collection is made up mainly as 

 follows : (i) the Lawrence Collection, consisting of about 12,000 

 specimens, mostly from Mexico, Central America, South America, 

 and. the West Indies ; (2) the Elliot Collection of Hummingbirds, 

 numbering about 2000, and one of the finest of its kind in the 

 world ; (3) the Smith Collection, 4000 specimens, from the Prov- 

 ince of Matto Grosso, Brazil ; (4) the Scott and Mearns Col- 

 lections of Arizona birds, about 6000 specimens. Also several 

 thousand North American, South American, European, and East 

 Indian specimens, besides a private collection of over 5000 birds, 

 belonging to Mr. George B. Sennett, which, by his kindness and 

 courtesy, is also available for use in scientific work. 



Explanation of Terms. — A few words explanatory of cer- 

 tain terms relating to classification used in the following pages 

 may not be out of place. 



The word group in classification has no technical standing, 

 being merely a convenient term to indicate collectively a series — 

 individuals, species, or genera, as the case may be, and varying in 

 number from two or three to many, as the context may indicate. 

 On the other hand, the terms kingdom, branch, province, class, order, 

 suborder, family, genus (plural, genera^, species, and subspecies, have 

 each a definite signification, and are always used in the same 

 sense. For example, birds belong to the Animal Kingdom 



* The collection of Monkeys, at present exhibited in the Bird Hall, is deposited here tempo- 

 rarily, awaiting place in the Mammal Hall when the addition to the building is completed. 



