1880, ] , Sandhill and Whooping Cranes, 109 
It is the present purpose to speak of this point of structure 
only as it exists in the two American species of cranes, Grus 
americana and Grus canadensis, with special attention called to 
its presence in the latter. 
That the trachea is remarkably convoluted within the sternum 
in the whooping crane (G. americana) has been pointed out and 
fully described by Dr. Elliott Coues, in his “ Birds of the North- 
west.” But the mistake is there made of stating (on the evidence 
of others, I believe) that in the sandhill crane (G. canadensis) the 
trachea is simple; and this supposed entire difference between the 
two species is presented as strong anatomical evidence of their 
distinctness, 7 
The fact is, however, that the trachea és convoluted within the 
keel in the sternum in G. canadensis as well as in G. americana. 
This I have determined by the examination of four sterna of can- 
_ adensis, three of which were prepared by myself from birds posi- 
tively identified as canadensts by the generally recognized external 
characters. Two sterna of americana have been examined: one 
the same that was described by Dr. Coues, and with which I have 
had the opportunity of comparing specimens through the cour- 
tesy of Dr. R. O. Sweeny, president of the St. Paul Academy of 
Natural Sciences ; the other a specimen recently prepared by Mr. 
Wm. Howling, taxidermist, of Minneapolis, Minn., and in whose 
collection I saw the adult bird from which it was taken. One side 
of the keel was neatly cut away by Mr. Howling, at my sugges- 
tion, and the specimen freely offered for use in the present con- 
nection. It is identical in structure with the St. Paul specimen, 
and is the one from which the drawing has been made. 
Although there is not such a radical difference as supposed by 
Dr. Coues, yet the two species are distinct in respect to their 
tracheal and sternal development. A glance at the drawings will 
show this at once. They are alike in so far as the trachea enters the | 
sternal keel in each. But in canadensis the whole sternum is — 
Smaller and less stoutly developed; the coils of the windpipe are 
Confined to the anterior half of the keel, and it isthis portion alone 
that is enlarged; there are only about eight inches (average of 
four specimens) of windpipe in the keel, to twenty-seven inches _ 
(average of two specimens) in americana ; the walls of the sternal o: 
Cavity are much more imperfectly ossified than in americana, 
where they are everywhere on the outside dense, hard bone. On 
