ANALOGICAL TESTS OF CIRCLES. 333 



the ocean, instead of the forest. These groups, there- 

 fore, are analogous, and do not disturb the harmony of 

 the series. We therefore pass onward to the last, namely, 

 the Crateropodince, or strong-legged thrushes, which we 

 compare with the order of Raaores, or the gallinaceous 

 birds. If an ordinary observer was asked what were the 

 most conspicuous distinctions of the gallinaceous order, 

 he would undoubtedly mention as among the first, the 

 great size and strength of their feet, and their short and 

 comparatively feeble wings. The first of these pecu- 

 liarities, in fact, is absolutely essential to them, because 

 they habitually hve upon the ground ; while the last^ 

 which in a tribe of flying birds would be an imperfec- 

 fection, among these is in perfect harmony with their 

 general habits. It would, moreover, be remarked, as a 

 third distinction of the rasorial group, that it contains 

 the largest birds in creation ; witness the ostrich, cas- 

 sowary, bustard, &c. Now what the rasorial order is to 

 the whole feathered creation, the Crateropodwce are to 

 the family of thrushes ; they have, as their name im- 

 plies, the strongest feet, they have the shortest wings, 

 and they are the largest birds in their particular group. 

 AVith three such strong and remarkable points of analogi- 

 cal resemblance, there can be no doubt that the Cratero- 

 podince are the representatives of ihtRasores; or, in other 

 words, that these two groups are parallel and analogous. 

 (409.) When results like these attend the com- 

 parison of a doubtful circle with one that is universally 

 deemed to be natural, there is good reason to believe that 

 we have discovered the true series ; for, however fancy 

 might deceive us in the first formation of a circle, it is 

 impossible to believe that so much harmony would result 

 from an erroneous application of a theoretical truth. 

 Nevertheless, it must be remembered that our group 

 has yet only been proved by one test. It has been 

 compared with the circle of the leading orders of birds ; 

 but this is not sufficient for complete demonstration. 

 The analogies, although strong, are nevertheless remote; 

 and it therefore is expedient, if not essential, that our 



