black; the peculiarity of the nostril has been noticed; thé
tubercle, even in an old male, of small size ; the irides brown ;
the head, neck, and the whole of the plumage pure white;
legs, toes, and intervening membranes slate-grey.
From the point of the beak.to the' end of the tail fifty-
seven inches. From the carpal joint to the end of the second
quill-feather, which is the longest“ tin the-, wing, twenty-one
inches and a half; tarsus four inches; middle toe and nail
five inches and three-quarters.
Its food and habits closely resemble those of 'the Mute
Swan.
The organ of voice appears, from one that I examined, to.
be like that of the Mute Swan ; but Mr. Pelerin ,haè>.found
considerable differences in various parts of tltev head;, the
description and measurements weré giveniin .a paper published
in the Magazine of Natural History Tor.1889’, page 178,>
from which the following is an extract."
The measurement of an adult cranium of , eaclr is; as ijol-r
lows ^Length, from the tip of the bill to;the base of:the
occipital bone“ in C. immutabilis, six inches and three-eighths;
C. olor, six inches and seven-eighths. Height, from .'thé bottom
of the lower mandible when closed, to the. top of the! protuberance
at the base of the bill, in C. immutabilisi, one inch
and five-eighths; C. olor, two inches. Height, from the base
of the under jaw to the vertex of the head, just’behind the,orbit
of the eye, in C. immutabilis,iy^6 inches and one-eighth ;
C. olor, two inches and one-quarter. In C. immgtabilis the bill
is rather more flattened, particularly in the middle, between the
dertrum, or nail, and the. nostrils; the protuberance at the
base of the upper mandible is less developed. In the Polish
Swan the cranium is highest at the supra-occipital portion ;
in the Mute Swan the cranium is highest at the supra-orbital
portion; but the greatest difference is perceptible on comparing
the occipital bones; the upper portion of this bone in
C. immutabilis protrudes considerably more, and there are
two oval foramina, one on each side just above the foramen
magnum', which are not present in any specimens of C. olor
that I have examined; the portion forming the boundary of
the external orifice of the ear is much more prominent, and
the condyle forms a more acute angle with the basilar portion
of the oecipital bone.
I have verified all Mr. Pelerin’s observations.