NATURAL SYSTEMS. — MACLEAY'S. O15 
written for the purpose of showing the identity of his 
theory with that of M. Fries, we do not discover any 
allusion to these osculant groups. Whether this omission 
originated in a desire to show that, in the main, his 
views were essentially the same as those of M. Fries, 
or whether he had already discovered that these small 
circles were, in fact, but part and parcel of the larger 
ones, does not sufficiently appear: certain it is, however, 
that this part of his former theory is passed over, both in 
the paper here alluded to, and in the Annulosa Javanica. 
Five is now declared to be the definite number ; and 
nothing is said, so far as we can trace, of the five small 
osculent groups. This alteration, the naturalist will im- 
mediately perceive, not only affects the details of the 
whole theory on the animal circle already exhibited 
’ (p. 203.), but likewise alters every diagram of the annu- 
lose groups given in the Hore Entomologice : for if the 
principles laid down in this latter work are adhered to, 
then our author’s views, in regard to the number of 
types in every natural group, most materially differ from 
that of M. Fries ; while, if we are to exclude osculant 
groups, as in the subsequent table given by Mr. MacLeay 
of the Ptilota*, or winged insects, then the whole of 
the diagrams given in the Hore Entomologice require 
re-modelling. This isso obvious, that we very much re- 
gret no explanation, upon so important a change, has been 
given. There is another distinction introduced by Mr. 
Macleay in his more recent essays on the quinarian 
theory, which also merits attention ; not so much as to 
the effect it has upon the groups themselves, but as 
having given rise to erroneous impressions on their pri- 
mary divisions, and apparently contradicting the former 
definitions. Our author has very clearly shown ‘the 
impropriety of M. Fries considering his centrum, or 
typical group, to be but one ; because, according to M. 
Fries’s own definition, this group is composed of two. 
** Centrum abit semper in duas series ;” yet, per 
* Linn. Trans. vol. xiv. p. 67. 
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