THE HORNED GREBE. 
199 
number of turns being twelve. Its length is 33 inches ; its width J inch at 
the upper part, towards the rectum only 3 twelfths. The cceca are 2 inches 
long, 2 twelfths in breadth, uniform, unless at the base, where they are 
narrower ; their distance from the extremity 3 inches. The cloaca is 
globular, 14 inches in diameter. 
The trachea is 91 inches long, of the nearly uniform width of 31 twelfths, 
unless at the lower part, when it is narrowed to 2 twelfths ^flattened in its 
upper half, and compressed in the lower ; the rings moderately firm, 180 in 
number. The Grebes differ from almost all other birds in having the 
bronchial rings complete and firmly ossified. In the present species, they 
are only 8 in number, the remaining part of the bronchi being membranous. 
There are the usual cleido-tracheal muscles ; the sterno-tracheal, part of 
which is continuous with the lateral muscles, but the inferior portion 
distinct, and attached to several of the rings ; there is also a single pair of 
inferior laryngeal muscles. 
The jugular veins are of vast size, and toward the lower part of the neck 
form an immense dilatation ; that of the left side being distended with 
coagulated blood to 9 twelfths of an inch, and so continuing until it enters 
the heart. ‘The other is £ inch in breadth. In this respect there seems to 
be an analogy to the diving mammifera, such as the seals and dolphins. 
THE HORNED GREBE. 
Podiceps CORNUTUS, Linn. 
PLATE CCCCLXXXI.— Male and Young. 
The period at which this little Grebe makes its first appearance, after the 
breeding season, on the waters of the Western States, such as the Ohio, the 
Mississippi, and their numerous tributaries, is the beginning of October, 
when I have seen them arriving and passing onward on wing at a consider- 
able height in the air, following the course of the streams. The generally 
received idea that birds of this genus perform their migrations on the water, 
is extremely absurd. I have already offered some remarks on this subject, 
but as too much cannot be said, when an erroneous notion extensively 
