NATURAL SYSTEMS. — MACLEAY’S. 213 
be applied. Such are the fundamental principles of 
classification contained in the Hore Entomologice ; the 
modifications which they subsequently received from its 
author, will be presently stated. 
(266.) The system of M. Fries is the next in order 
of succession ; for, although it was applied by this dis- 
tinguished botanist only to a natural group in the 
vegetable kingdom, its principles are too important not 
to be equally deserving the attention of the zoologist. 
It is very remarkable, that this consummate botanist, 
totally ignorant of the previous publication of the Hore 
Entomologice, should have detected the same principles 
of circular affinities therein developed, and should have 
illustrated them, by analyses, much more fully. Yet, 
although these naturalists agree in considering the cir- 
cularity of groups to be the first principle of the natural 
system, they differ in the determinate number of their 
groups ; those of Mr. MacLeay being, in fact, ten (or, ac- 
cording to his subsequent belief, five); and those of M. 
Fries four. It seems, however, that the centrum, or 
typical group of the German botanist, is always divisi- 
ble into two series (sed centrum abit semper in duas 
series); and that each of his series or groups is a circle, 
appears evident from the following words:— Omnis sectio 
naturalis circulum per se clausum exhibet, that is, every 
section, series, or group, forms, of itself, a circle. 
Hence it follows, that, as one of M. Fries’s groups, ac- 
cording to his own account, is always divisible into two, 
thus their total number is not four, but five. The dif- 
ference, therefore, between this theory and the last is 
rather nominal than real: for as M. Fries at the same 
time detected the theory of representation, by which the 
contents of one circle typified the contents of a neigh- 
bouring circle, this, of course, led him clearly to un- 
derstand and to define the difference between analogy 
and affinity. It is plain, therefore, that the three great 
principles of natural arrangement given to the public in 
the first instance by Mr. MacLeay, were also discovered 
by M. Fries; we say discovered, in contradistinction 
P 3 
