488 Mr. N. A. Vigors on the Natural Affinities 



appear to be those which partake most equally of the advantages 

 of both elements ; and the aberrant groups those which discover 

 a more predominant inclination to either. Of the five families into 

 which the order before us branches out, we may, in this point of 

 view, pronounce those two to be most typical which inhabit the 

 land, but derive their support from the water ; or, to speak more 

 correctly, which derive their whole support from the latter ele- 

 ment, without possessing those powers of swimming or diving 

 which are peculiar to the true water-fowl. The exclusive food 

 of such groups will be fish, water reptiles and insects, mollusca, 

 and animalcula ; and their distinguishing external characters, 

 length of legs and bill, — the former for the purpose of wading, 

 the latter for that of seizing their prey, or of extracting it by suc- 

 tion from the waters or marshes. Of the three remaining fami- 

 lies, two, as I have observed in an early part of this inquiry, 

 will be found to deviate from the more typical, in their food and 

 manners being more terrestrial, and their general appearance 

 and structure more conformable to that of some groups of the 

 preceding order of Rasores : while the third, by its capability of 

 swimming and the rudiments of the natatorial membrane that 

 connects the fore toes of some of its species, equally deserts the 

 same type, and goes off, on the other hand, to the Natatores. 

 Taking these peculiarities into consideration, we may venture to 

 view the order according to the following arrangement, placing 

 as usual the more typical families in the centre* : 



The following disposition distinguishes the normal and aberrant families : 



Normal group. 

 Rostris longis, ad sugendum prse- f Ardeiaa. 



Normal group. 

 ngis, adsugendi 

 cipueidoneis |^ ScolopacidtB. 



IS 



Aberrant group. r RalUdcE. 



R05tris brevibus, ad captandum, ) Ckaradriada. 

 baud sugendum idooeis • • ] y, . , 



K. uruida. 



Grtcida. 



