NATURAL SYSTEMS. MACLEAy's. 215 



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, '^^hether this omission 

 originated in a desire to show that, in the main, his 

 views were essentially the same as those of jM. 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 

 esculent groups. This alteration, the naturalist will im- 

 mediately perceive, not only affects the details of the 

 whole tlieory on the animal circle already exhibited 

 (p. 203.), but likewise alters every diagram of the annu- 

 lose groups given in the Horce Entomologicce : 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 Ptilofa*, or winged insects, then the whole of 

 the diagrams given in the Horce Entomologicce require 

 re-modelling. This is so obvious, that we very much re- 

 gret no explanation, upon so important a change, hasbeen 

 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 j " yet, per 



* Linn. Trans, vol. xiv. p. 67. 



p 4 



