488 Mr. N. A. Vicors 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 pre- Ardeida. 
cipue idoneis ........ Scolopacide. 
Aberrant group. Rallide. 
Rostris brevibus, ad captandum, Charadriade. 
haud sugendum idoneis . ; 
Gruide. 
Gria. : 
