182 ON THE CLASSIFICATION OF BIRDS. 
prehensive circle there is one group eminently distin- 
guished by crests, stiU holds good in this ; and that the 
Grallatores likewise present us with another group of 
equal rank, where the wings are convex and feeble, the 
bill short and hard, and the feet remarkably large and 
strong, is abundantly proved by the rads, which are the 
aquatic poultry of the waders. Imperfection of foot, 
moreover, which is another of the fissirostral characters, 
must not be looked for in an order like this, where the 
whole of the families seek their food on the ground, and 
must therefore he able to walk remarkably well. These 
considerations, joined with others, one of which we shall 
presently notice, have decided us in considering the 
Ardeadee as the fissirostral type of the Grallatores ; and 
we therefore pass to the ne.xt analogy, or that which 
we consider to exist between the IhU and the Tmui- 
Tostres. The different modifications of the Linna;an 
genus Tantalus, certainly comprehend those birds 
furthest removed from the typical perfection of the 
waders : their bill, although long, is more solid ; the face, 
and sometimes the head, is naked (as we see in the 
Ampelida: and other corresponding groups) ; and the 
plumage, totally unlike the more typical waders, is ge- 
nerally glossed with rich metallic colours : had they but 
remarkably short legs, they would, in fact, be gigantic 
humming-birds ; and even that which is entirely crimson 
finds its representative in such birds, similarly coloured, 
as analysis proves to be tenuirostral types. The ana- 
logy of the Rallidm to the Itasnres has already been 
alluded to, and is too obvious to require further eluci- 
dation. We have, unfortunately, no space for defining, 
so far as our researches have yet gone, what appear to 
be the precise limits or the connecting links of these fa- 
milies : but the primary groups, as now arranged, furnish 
a strong corroboration that the series is natural, merely 
from this result, that we find the two first distinguished 
by having the hinder toe, where it exists, very small and 
elevated ; while in the aberrant group, composed of the 
Ardeada, the I'antulidte, and the llalUda, the hinder 
