REPORT ON ZOOLOGY. 153 



in any circle are connected hy relations of affinity, corre- 

 sponding groups in two co)itigt(ous circles are connected by 

 relations of analogy. Mr. MacLeay has also observed*, that, 

 in almost every group, one of the Jive minor groups, into 

 which it is resolvable, bears a resemblance to all the rest ; or, 

 more strictly speaking, consists of types ivhich rejjresent those 

 of each of the four other groups, together with a type peculiar 

 to itself. These principles had been partly brought forward by 

 Mr, MacLeay, two years before, in the first part of the work 

 above mentioned. It was then, however, with exclusive refer- 

 ence to the natural arrangement of the Lamellicorn Insects, in 

 which group we are told it was that he was first led to detect 

 them. It was not till 1821 that he applied them more generally, 

 in showing that a tendency to circles prevailed throughout na- 

 ture, and that the same principles which he had observed to re- 

 gulate the natural arrangement of the above group, appeared to 

 regulate that of the entire animal kingdom. It is somewhat re- 

 markable, and certainly tending to confirm Mr.MacLeay's views, 

 that in the same year, and apparently without any knowledge 

 of the first part of the Hone Entomologicce, M. Fries, in Ger- 

 many, published his Systema Mycologicum, in which he an- 

 nounced principles somewhat similar to those above stated, as 

 regulating the natural distribution of Fungi. This gave rise to 

 a paper from Mr. MacLeay, read the following year to the Lin- 

 naean Societyf, in which he commented on this identity (so ftir 

 as the identity prevailed,) of the principles which they had 

 respectively adopted. He also pointed out wherein they dif- 

 fered; one difference consisting in the determinate number, which 

 M. Fries considei-ed as four, being the same as that formerly ad- 

 vanced by Oken. Mr. MacLeay's arrangement of the Lamel- 

 licorn Insects in the first part of the HorcB Entomologica; was 

 the result of rigid analysis, and is therefore deserving of the 

 greatest attention ; that however of the entire animal kingdom 

 in the second, was chiefly deduced from synthetical investigation, 

 and was moreover confined to the larger and more important 

 groups. It is not, therefore, surprising that many endeavours 

 should be made subsequently by himself, as well as by those 

 who had adopted more or less of his theory, to illustrate 

 his new principles by a more close application of them to 

 different departments of zoology. The first result was a paper 

 by Mr. Kirby, in 1822:|:, in which he described some insects that 

 appeared to exemplify Mr. MacLeay's doctrine of affinity and 

 • Hor. Ent., p. 518. f Linn. Trans., \<A. xiv. p. 16. 



X Linn. Trans., vol. xiv. p. 93. 



