SPECIFIC CHAEACTEllS OF BIllDS. 535 
coTefed at its base with a very fine down. The breast fea- 
thers are rounded, compact, and abruptly separated from 
the lax elongated feathers of the lower pectoral and abdo- 
minal regions. 
The J ay, which is also a true Corvus, is also easily dis- 
tinguished by the peculiar loose texture, and elongated 
form of the whole under surface and neck, as well as by 
the wing coverts, which are compact and stiff. 
The next tribe to which I shall apply the character, is 
the great group of waders, distinguished by the name of 
Ardeoe. 
The Common Heron might be characterised as follows : 
A. cinerea,— Plumis verticis elongatis, attenuatis, laxis; 
cervicis inferioribus laxissimis scapularibusque elongatis, 
apice producta, lineari, acuta. 
The Garzetta^ — Plumis verticis elongatis laxissimis, bar- 
bis simplicibus, cervicis inferioribus elongatis, laxissimis, 
scapularibus ad caudse apicem protensis, tortis, barbis re- 
raotissimis simplicibus secundis. 
A. Agami might be characterised by the curved and li- 
near form of the lateral neck feathers, the peculiar texture 
of the pectoral and ventral feathers, &c. 
In short, I have not been able to find any two herons 
of acknov/ledged and indubitable species, that did not pre- 
sent obvious differences in the plumage. 
Of the genera proposed, there now only remains that in 
which the numerous family of ducks is included ; and here 
it is, in general, easy to mark the differences. 
A. citrata, for instance, is distinguished at once by the 
imdulated form of the inner quills, from the white swan, 
A. mollissima may be taken as an example of the great va- 
riety of plumage exhibited in one and the same bird, being 
peculiarly easy to distinguish, on account of the remark- 
able grouping of the feathers. Those of the head are, in 
