732 PLOVER 
southern extremity of Africa. The same may be said, mutatis 
mutandis, of two other cognate forms, C. virginicus and C. fulvus, which 
respectively represent C. pluvialis in America and Eastern Asia, where 
they also are known by the same English name. The discrimination 
of these two birds from one another requires a very acute eye, and 
room is here wanting in which to specify the minute points in 
which they differ ;+ but both are easily distinguished from their 
European ally by their smaller size, their greyish-brown axillary 
feathers, and their proportionally longer and more slender legs. 
All, however,—and it is the same with the Grey Plover,—undergo 
precisely the same seasonal change of colour, greatly altering their 
appearance and equally affecting both sexes. In the course of 
spring or early summer nearly the whole of the lower plumage 
from the chin to the vent, the greater part of which during winter 
has been white, becomes deep black. This is partly due to the 
growth of new feathers, but partly to some of the old feathers 
actually changing their colour, though the way in which the 
alteration is brought about is still uncertain.? A corresponding 
alteration is at the same season observable in the upper plumage ; 
but this seems chiefly due (as in many other birds) to the shedding 
of the lighter-coloured margins of the feathers, and does not produce 
so complete a transformation of appearance, though the beauty of 
the wearer is thereby greatly increased. 
The birds just spoken of are those most emphatically entitled 
to be called Plovers; but the DorrTEeREL, the group of Ringed 
Plovers before mentioned (KILLDEER) and the LApwiING, with 
their allies, have, according to usage, hardly 
less claim to the name, which is also ex- 
tended to some other more distant forms 
that can here have only the briefest notice. 
Among them one of the most remarkable 
is the Pluvianus or Hyas xgyptius of orni- 
thologists, celebrated for the services it is said to render to the 
crocodile—a small bird whose plumage of delicate lavender and cream- 
Puouvianus. (After Swainson.) 
1 Schlegel (Mus. Pays-Bas, Cursores, p. 53) states that in some examples it 
seems impossible to determine the form to which they belong; but ordinarily 
American specimens are rather larger and stouter, and have shorter toes than 
those from Asia. 
* It is much to be regretted that ornithologists favourably situated in regard 
to zoological gardens have not used more extensively opportunities which might 
there be enjoyed of conducting useful observations on this subject and others of 
the kind. Elsewhere it would be hardly possible to carry on such an investiga- 
tion, and even in the best circumstances it would not be easy and would require 
unremitting attention. The results of some partial observations superintended 
by Yarrell in the gardens of the Zoological Society of London are given in its 
Transactions (i. pp. 18-19). Little of this nature has been done there since. 
