196 
THE RUBY-THROATED HUMMING-BIRD. 
purple, spotted with black, varying to crimson, orange, and deep black. 
Sides of the same colour as the back ; the rest of the under parts greyish- 
white, mixed with green. 
Length 84 inches, extent of wings 44 ; bill along the ridge 3, along the 
gap | ; tarsus }, toe 4. # 
Adult Female. 
The female differs from the male in wanting the brilliant patch on the 
throat, which is white, as are the under parts generally, and in having the 
three lateral tail-feathers tipped with the same colour. 
Dimensions the same. 
Young Bird. 
The young birds have the under parts brownish-white, the tail tipped 
with white, and are somewhat lighter in their upper parts. In autumn the 
young males begin to acquire the red feathers of the throat. 
On depriving a specimen of this bird of its feathers, one finds its 
proportions very different from what he may have previously imagined. 
Thus, the body is remarkably robust, of an ovate form, much deeper than 
broad, on account of the extreme size of the crest or keel of the sternum, 
"which is so extended as to leave for the abdomen a space not more than a 
fifth of its own length. The feet, although very small, are yet proportionally 
as large as those of a Cormorant ; the femur and tibia being relatively large, 
"while the tarsus is extremely short, and the toes of moderate size, the anterior 
incapable of being widely spread, and the middle or third scarcely exceeding 
the two lateral ; in which respect the foot has some resemblance to that of 
the Swifts. The hind toe is articulated remarkably high on the tarsus, it 
being placed very nearly at the height of one-third of its length. The bones 
of the wings are very short ; the humerus and cubitus extremely so, although 
proportionally strong. The neck is very elongated, being 10 twelfths of an 
inch in length, whereas the body, including the coccyx, is only 9 twelfths. 
The head is rather large, depressed in front, with a deep hollow between 
the eyes, which are very large, and the bill is disproportionately elongated. 
The pectoral muscles are of extreme size, exceeding by much the entire bulk 
of the rest of the body with the neck and head, the height of the crest of the 
sternum being 4 twelfths, or nearly half the length of the body. The body 
of the sternum is remarkably flat, and so thin as to be almost perfectly 
transparent ; it is narrow anteriorly, where it is 24 twelfths in breadth, but 
gradually enlarges to 4 twelfths ; the posterior edge forms a semicircle, and 
is destitute of notch. The pubic bones almost meet in front, where they are 
cartilaginous. The heart is extraordinarily large, occupying half the length 
of the cavity of the body, of an elongated conical form, 84 twelfths long, and 
