S82 Zoological Proceedings of Societies, 



menced on the 28th of April, of the quinary arrangement of the 

 Insessorial Birdsy and the circular series of affinities by which 

 the subdivisions return into themselves : and he entered upon the 

 discnssion of the question, arising out of the subject, which had 

 been postponed on that evening. He explained the advantages 

 which the present mode of investigating nature possesses over all 

 the artificial systems which have hitherto prevailed ; dwelling on 

 the present occasion more particularly on two points ; namely, — 

 First, on the advantages which a mode of arrangement founded 

 upon the affinities of groups exhibits, in giving the student an 

 uninterrupted view of the connecting characters of all, the know- 

 ledge of one group leading immediately to the knowledge of that 

 which succeeds ; whereas in the systems which have hitherto been 

 applied to Natural History, and which have been exclusively 

 founded on division, the student, when he quits his investigation 

 of one group, has no clue to the knowledge of that which is to 

 follow : — and Secondly, upon the advantages resulting from the 

 same method of arrangement, as exhibiting an uniformity in the 

 mode of investigating corresponding or analogous groups of nature. 

 This latter principle he illustrated by pointing out the analogous 

 relations which exist between the five orders of the Mammalia^ 

 and those of Ornithology ; and he drew the conclusion, that the 

 student, having attained a knowledge of the typical characters in 

 the five orders of either of these classes, is immediately led, by 

 making allowances for the respective peculiarities that distinguish 

 the two groups — i. e. mutatis mutandis — to a knowledge of the 

 typical characters of the five orders belonging to the other classes. 

 He adverted to many other corresponding analogies in the animal 

 kingdom ; and, drawing the inference from the great mass of in- 

 formation which already corroborated these views in so many de- 

 partments of nature, that similar analogies would probably be 

 found to exist between other groups of equal degree not yet in- 

 vestigated, he presumed that the mode of consulting Nature, 

 which thus opened a passage from the knowledge of one group to 

 the knowledge of all which correspond with it in equal rank, has 

 9 claim to h<=* considered :is of superior advantage and importance'. 

 He then tofj-k notice of some objections which had been brought 



