18 
OBJECTS OF THE MUSEUM AND 
Exhibited 
Systematic 
Series. 
Reserve or 
Study 
Systematic 
Series. 
in describing and defining tliem explained by means of 
illustrative examples. This has been already carried out in 
the Department of Mineralogy, in a series of cases placed on 
the north or left-hand side of the gallery containing the rest of 
the collection. The introductory series to the zoological and 
botanical collections has just been referred to as under arrange- 
ment in the Central Hall. 
II. The Exhibited Systematic Series, in which the most 
important types of animal, plant, or mineral forms are shown, 
by means of carefully-selected and well-preserved specimens, 
arranged in a systematic manner, or one which exhibits, as far 
as may be, their natural relations to each other. Classification is 
an important feature in this series, which should be so complete 
and so arranged as to ensure that every \T.sitor to the Museum 
can find without recourse to assistance from the officials every 
well-known and very distinct form of animal, plant or mineral, 
and satisfy himself about, at least, its external characters. In 
carrying out this ideal, great modifications must be made in 
practice, partly depending upon the readiness or the reverse, 
with which the members of different groups lend themselves 
for exhibition, partly upon the exigencies of space, and partly 
upon special circumstances which render the exhibition of the 
leading forms of some groups of more interest than those of 
another. 
While the two series above mentioned have for their object 
the diffusion of scientific knowledge, the next ministers mainly 
to its advancement, and thus between them the twofold object of 
a National Museum of Natural History is carried out. 
III. The Eeserve or Study Systematic Series contains all 
those exceedingly numerous specimens (in many groups, the great 
ljulk of the collection in fact) showing the minute distinctions 
which are required for working out the problems of variation 
according to age, sex, season, and locality, for fixing the limits 
of geographical distribution, or determining the range in geo- 
logical time: distinctions which, in most cases, can only be 
appreciated when the specimens exhibiting them are kept under 
such conditions as to admit of ready and close examination and 
comparison. It is to this part of the collection that zoologists 
and botanists resort to compare and name the animals and plants 
