﻿EXTERNAL ANATOMY. SCANSORIAL FEET. 141 



much more support backwards, in such a position, than 

 any other birds. In order to effect this, nature has 

 recourse, so to speak, to other means than those she 

 usually employs. The hinder toe and claw is either 

 enormously developed, and the tail has no additional 

 power given it (as in the case of Climacteris and Sitta), 

 or, — if still greater support is necessary than would be 

 acquired by this structure, — the tail itself, by a peculiar 

 formation, is made to perform the same office as the 

 hind toe, but with infinitely more effect. This brings 

 us to the point at issue. The Sitta derives its sole sup- 

 port when climbing from its posterior toe, which is conse- 

 quently unusually large. Dendrocolaptes , on the other 

 hand, being a much more powerful and rapid climber 

 (as we have proved by the structure of its anterior 

 toes, and have witnessed by personal observation), 

 requires a much greater support backwards, propor- 

 tionate to its power of advancing forwards. The tail 

 is, therefore, enlarged and strengthened in such a way, 

 by rigid points which stick into the bark, that the office 

 of the hind toe is almost superseded, and its size is 

 consequently not greater than in the generality of birds. 

 We should not have gone into these explanations merely 

 for the purpose of refuting the sort of criticism to 

 which on another occasion we have been exposed*, but 

 because they will deter the young ornithologist from 

 forming hasty judgments upon matters which more ex- 

 tended investigation would place in a different light. 

 These details will also demonstrate, what is of far 

 greater interest, another and a new proof of that har- 

 mony of design, and that infinite ^diversity of ope- 

 rations " which the Infinite Being has manifested in 

 these his glorious, yet lower, works. 



(124.) There are yet three other modifications of 

 the scansorial foot which must not be passed over, 



* Vide the periodical critics, on the " Preliminary Discourse." The few 

 of our readers who may possibly be influenced by such misrepresentations 

 and falsehoods, will find them very neatly exposed in the " Entomological 

 Magazine " for April, 1835. 



