4. VARIATION. 
The phases of Variation, or Modification of Strncture and Plumage display 
among the birds of Celebes may be conveniently considered undei the follon „ 
headings: ^ ^iffprences peculiar to the individual. 
1. Individual ^ naces, subspecies, or species. 
s: stra’l cr:nl::;:ras pecuuar summer and win.r plumages in birds. 
4. Sexual Differences; the — ^ aecadence of the 
5. Changes depending 
individual. 
1. Individual Variation. 
The assumption that no two individuals are ever 
be completely justified by facts. No one, pio ^ possible comparison 
as the zoologist, who is called upon to make the closest po sibie P 
of large series of individuals of the same race. In the corns of ivut he 
presenf book, for instance, which is chiefly based "P”" . 
Lnal coverings, and bills, legs and feet of Celebesian b.rd^ w * —a 
reference to then- skeletons — some thousands of specimens moreover 
yet to the best of our knowledge no two of them --“^fy/^^^rbeUeve 
in the text several thousand measurements of paita vii e , 
that hardly any two cases occur in which four ^ to ^om a know- 
are the same. There are some very ° aildren, are 
ledge of this infinite diversity of form is percep i , differences in blades 
conscious of the peculiarities of individual their eyes 
of grass; others, and amongst them men of the idea 
opened to the fact, and assert that exactly t e , d by the latter, with 
oL uniformity of the indriiduals of a is l-tly 
its consequence, that species were P longer meets the needs of our 
the result of a system of ! of individuals possessing some 
time. There are of course species s other group, — but each indi- 
character (or characters) never so oun m ^ nomenclature can only 
vidual has its own peculiarities, and an ideal system 
