414 Mr. N. A. Vicors on the Natural Affinities 
greater extent in the type of the Struthionide, where one of the 
front toes is also deficient. This character, which indicates the 
habit of running, brings the Charadriadæ in a natural arrange- 
ment into close contact with the Struthionide. So that we may 
at once decide that the passage from the Gallinaceous to the 
Wading order takes place at that point where the two extreme 
subdivisions of the latter are united, as we shall shortly observe, 
by the genera Œdicnemus of Cuvier and Psophia of Linnæus. 
The genus Otis, Linn. seems to be the group among the Rasores 
that immediately meets them. 
The two conterminous orders, Grallatores and Natatores, form- 
ing, when united, a division of the entire class, which may be 
entitled Aquatic Birds, it may readily be concluded that they 
approach each other by such gradations as render it no easy 
task to fix the exact limits of each. This is so much the case, 
that the most obvious characters of each order are in many in- 
stances transferred to groups of the other. ‘Thus we find the 
webbed feet of the Natatores among birds which do not swim, as, 
for instance, the Recurvirostra, Linn., and Phenicopterus, Linn. 
On the other hand, we have groups which do swim, such as the 
genera Rallus, Linn., Gallinula, Briss., and Hematopus, Linn., 
and which yet possess the divided toes of the Grallatores. Again, © 
we may observe other Swimming Birds, such as the lobated Fu- 
* lica, Linn., and Phalaropus, Briss., the feet of which may be said 
to be neither webbed nor divided, but to partake of each charac- 
ter. Various modes of classing these birds have consequently 
been adopted by systematic writers. Linnæus has placed the 
before-mentioned genera Phenicopterus and Recurvirostra among 
his Anseres, or our Natatores. But the character of their webbed 
feet is neutralized by the extreme length and forward position of 
their legs, which totally prevent their swimming: and these lat- 
ter characters, together with the nakedness of their thighs and 
their habits of life, decidedly place them among the Grallatores. 
To 
