XXIV INTRODUCTION. 



before alluded to, though in general he has discriminated, limited, and located his 

 groups with a felicity peculiar to himself, yet in consequence of his assumption of 

 the above system as an invariable guide, has, in many instances, been induced to 

 separate groups that are evidently nearly related, and to scatter them far and wide 

 through his various sections. Mr. Mac Leay, likewise, by assuming the number 

 Jive for the universal regulator of every group — whether primary, intermediate, or 

 ultimate — of the whole animal kingdom, though in many cases it may prevail, has 

 by no means made it clear that it is the keystone of the mighty arch of nature, or 

 the clue by which her mazy labyrinth may be traced through all its windings and 

 recesses. 



Whoever considers the infinite ramifications of the Animal and Vegetable King- 

 doms , the vast number of groups differing in rank and value, and rolling wheel 

 within wheel, almost ad infinitum, of which each consists ; may readily conceive 

 that the formation of a numerical system, whether the number assumed as the 

 regulator be two, three, four, five, or seven, is a labour of no very difficult accom- 

 plishment ; but to construct it so that the groups of each section, from the primary 

 to the ultimate, shall be equal or nearly equal in value, which alone can prove that 

 it is the system of the Creator, — hie labor, hoc opus est. 



Mr. Stephens, in his Systematical Catalogue of British Insects, containing, I 

 believe, the last that has been published, has given a still different, and, upon the 

 whole, an improved arrangement, in which he implicitly follows neither of his 

 predecessors, and has taken great pains, as far as his means and limited subject 

 permitted, though in some things he also appears to me mistaken, and who is notr 

 to follow the light afforded him by nature. Sir J. F. W. Herschel's observations 

 on this subject merit particular attention. " The classifications by which science 

 is advanced, however, are widely different from those which serve as bases for arti- 

 ficial systems of nomenclature. They cross and intersect one another, as it were, 

 in every possible way, and have for their very aim to interweave all the objects of 

 nature in a close and compact web of mutual relations and dependence." 5 



5 Disc, on the Study of Nat. Philosophy, Cab. Cycl. xiv, n. 134. 



