183 
orbicular, by being greatly extended late- 
rally, and filling up the whole of the low- 
er part of the breast-bone. Thus the 
lower part of the cavity that receives the 
trachea is very convex on the inside, and the 
bone is so extremely thin and membran- 
aceous that the flexuous course of the tra- 
chea is easily defined through it. There 
are other slight differences, but as we have 
given correct figures* it is unnecessary to 
enlarge upon the subject. 
The Wild Swan measures about four 
feet, ten inches in length, and seven feet in 
the expansion of its wings ; but we have 
seen specimens which measured more, and 
others less. 
The female does not differ from the 
male in plumage, but its weight and di- 
mensions are somewhat less. 
This bird is found in all the Northern 
countries Iceland, Lapland, the De- 
serts of Tartary and Siberia, as far as 
Kamtschatka, also in America and is not 
uncommon at Hudson's Bay. It visits 
* In the plate the outer part of the bone is taken off, 
in order to expose the internal contents to view. 
