MAMMALOGY — MILLEE 401 



bats and moles, to grinding, as in elephants, cattle, and horses, to a 

 combination of cutting and grinding, as in rats and beavers, or to 

 all-round utility, as in men and pigs). 



Systematic mammalogy therefore resolves itself into the investi- 

 gation of all of these features and of any others which may assist 

 in the accurate determination of different kinds, and in the grouping 

 of these kinds according to their relationships. In all of this part of 

 the study it is of prime importance to distinguish between those 

 peculiarities which are constant specific characters and those which 

 are individual features of the sort normally occurring in the two 

 sexes and in the various ages of one animal. Many specimens of each 

 mammal must be examined and compared before the differential 

 peculiarities can be clearly distinguished from those due to the diverse 

 sorts of individual variation. Many more are needed to determine 

 the status of local races, because a series from one place may be obvi- 

 ously different from a series from another, when one or two speci- 

 mens from each would be indecisive. After this more specimens of 

 each kind are needed from as many different localities as possible, 

 in order to determine the limits of geographical ranges. Field ob- 

 servations such as those which have contributed to our knowledge of 

 birds are of relatively little value in studying mammals, because 

 most mammals keep themselves hidden from human sight. 



In mammalogy, as in every other branch of present day knowl- 

 edge, an important element in the routine of the active worker is the 

 task of keeping abreast with the ever increasing current of litera- 

 ture. Arising from the work done by members of museum staffs 

 and by individual students, given out through the channels of books, 

 periodicals, and the journals of scientific societies, finding its source 

 in the two Americas, in England, France, Spain, Belgium, Holland, 

 Denmark, Norway, Sweden, Germany, Italy, Hungary, Russia, the 

 Malay States, Java, Australia, and Japan, there flows a growing 

 stream of publications about mammals. To be ignorant of the in- 

 formation which these treatises, monographs, papers and notes con- 

 tain would be a fatal handicap to anyone who aspired to become a 

 serious student. One of the recognized elements of the work in our 

 larger museums therefore consists in maintaining a constant fa- 

 miliarity with the literature of mammalogy, a task which is light- 

 ened by the aid of the Zoological Record (London), Biological Ab- 

 stracts (Menasha, Wisconsin), the cards issued by the Concilium 

 Bibliographicum (Ziirich) and the lists of current publications 

 which appear quarterly in the Journal of Mammalogy. Trouessart's 

 Catalogus, Palmer's Index Generum Mammalium and Sherborn's 

 Index Animalium are other well known standard works. The more 

 important mediums of publication in which the essential part of the 

 recent literature has appeared are as follows: In Washington we 



