1886.] CUBITAL COVERTS OF BIRDS. 193 
with any conspicuously-marked Pigeon of the normal type (Columba 
guinea, for example, fig. 14 a) on the other. The difference, to me, 
appears both striking and significant. Perhaps I. may be allowed 
to remark that the characteristic differences between Goura and the 
normal Pigeons are represented in the very useful series of coloured 
illustrations now. posted up outside the Western Aviary in the 
Society’s Gardens. 
In addition to the difference already noted between the true 
Pigeons and Goura, the following points of agreement and of 
difference between the two groups may be considered :— 
In the normal Pigeons an oil-gland is present; but is absent in 
Goura. 
In the normal Pigeons the tail-feathers are 12 in number ; while 
there are 16 in Goura. 
In the normal Pigeons the pterylosis is columbine ; and is galline 
in Goura. 
In the normal Pigeons ceca are present; but are absent in 
Goura. 
In the normal Pigeons a gall-bladder is present: no gall-bladder 
in Goura. 
- In the normal Pigeons incubation lasts 16 days; but extends to 
28 days in Goura. 
_ In addition to these peculiarities reference may be made to the 
bird’s pheasant-like habits, to certain peculiarities of the urosacral 
and of the caudal vertebree, to the number of the cervical vertebre, 
to the absence of pterygoid processes, and to other features referred 
to by Prof. Huxley (P.Z.S. 1868, p. 302) and by Prof. Parker 
(Tf. Z. S. v. p. 151, 1863). Dr. Sclater (Ibis, 1880, p. 407) refers 
to certain peculiarities of the tarsus, in addition to the differences 
just noted, as evidence in favour of separating Goura from the 
Pigeons. 
The main differences that distinguish the wing of the Peristeropod 
Gallinze from that of the Birds of Prey have already been pointed out. 
It remains to add that the prominence of distal overlap introduced 
by Zalegalla, Crax and its allies, becomes more accentuated in 
Numida, and thence, through the Tetraonide (fig. 15, p. 194), reaches 
its greatest development amongst the Gallinz in the typical Pheasants. 
A progressive increase of distal imbrication can be traced, in the first 
stages, only in the first, or posterior, row of median coverts, then in the 
second, and the third, and so on, until in Polyplectron all the more 
conspicuous feathers in the closed wing of the living bird seem to lap 
from the proximal towards the distal side of the wing. Excellent 
examples of the features referred to may be easily observed in the 
Society’s Pheasant Aviary, where Lophophorus impeyanus, Huplocamus 
swinhoti, Phasianus reevesi, and Polyplectron chinquis well display 
the feature referred to. A reference to the annexed figure of 
Luplocamus swinhoii (fig. 16, p. 194) will serve to make the general 
disposition clear. 
Pavo follows a slightly different pattern; and it is a point worth 
