41 



sidering metamorphosis as the corner-stone of his 

 system, may divide all insects into such as un- 

 dergo this transformation, and such as do not. 

 Hence, it follows, that every one may form a binary 

 system of his own, provided he closely attends to, 

 and 6 possesses distinct conceptions on, positive 

 and negative characters' ; the only requisite, as its 

 advocates affirm, for this mode of arrangement. 

 As for preserving the natural affinities of groups, 

 it is by no means necessary to the systems in ques- 

 tion that any regard should be paid to such matters; 

 their advocates, very judiciously, do not insist on 

 such considerations, nor do they attempt to point 

 out in what way nature gradually passes from one 

 group to another." 



On the Cuckoo and on Migration, in Philosophic 

 Transactions, by Edward Jenner, M. D. 1797 — 

 1824. 



On the Cuckoo, in Manchester Transactions, by 

 Mr. Black wall, 1824 ; and in Magazine of Natu- 

 ral History, Vol. VIII, by various writers. 1835. 



In these several Journals will be found a full 

 elucidation of the habits, nidiflcation, &c, of that 

 extraordinary bird, the Grey Cuckoo (Cuculus 

 canorus, Linn.) The celebrated Dr. Jenner first 

 explained the peculiar habits of this bird, which 

 were little laiown before his time. The student 

 will read these papers with pleasure and advan- 

 tage. 



Illustrations of ^British Ornithology, by P. J. 

 Selby, Esq. Land Birds. Edinburgh. 1825. 8vo. 

 10s. 6d. 



d 3 



