that connect the Orders and Families of Birds. 401 



groups will appear, of whose place in nature I must speak with 

 hesitation. But while it must be acknowledged, that some defi- 

 ciencies will intervene in the chain of evidence by which I would 

 endeavour to establish the existence of a uniform succession of 

 affinities in the feathered creation, it must be equally observed, 

 that there is no contradiction to it. The chasms that occasionally 

 present themselves are such as may be supposed to originate in 

 our limited knowledge of the subject. Time may supply the 

 absent links of our chain, as it has already supplied, and still 

 continues to supply many : and, judging from the past, we need 

 not despair of finding every deficiency filled up from the daily 

 discovered relics of a former world, or the exhaustless recesses 

 of the present. 



It has been observed* that, if the natural groups into which 

 the animal kingdom is divided bear a uniform analogy to each 

 other, — a principle which is among the most important of those 

 involved in the system which I wish to illustrate, — it is a necessary 

 consequence that their number should be definite. The primary 

 groups of those departments of the animal kingdom which have 

 hitherto been investigated, have been ascertained to be limited 

 to five ; and the first great divisions of birds will be found to 

 branch out into a similar number. The characters of the types 

 of these leading groups are so strongly and distinctively marked, 

 that they could not escape the comprehensive eye of Linnaeus, 

 whose tact in seizing upon the grander affinities of natural ob- 

 jects, and bringing them together in their greater groups, has 

 left him without a rival among naturalists. Four of his orders, 

 which possess such distinctive characters as will not admit of 

 their being confounded together, may be at once adopted with 

 some slight modification. The powerful and strongly-hooked 



* See " Remarks on the Identity of certain general Laws," &c. &c. by W. S. Mac- 

 Leay, Esq. in the present volume of the Transactions, p. 55. 



74; beaks 



