50 DR. E. CRISP ON THE ANATOMY {Jan. 10, 
examined them, as I had done on former occasions, in relation to the 
two questions above referred to. As the evidence of one inquirer in 
reference to the habits of this or of any other bird is comparatively 
valueless, let me quote a few authorities upon the subject. 
Montagu, in his Ornithological Dictionary, says he “discovered 
the nest of this bird in consequence of the old bird flying, with a fish 
in its bill, to the young. These were nearly fledged, but incapable of 
flight ; and the moment the nest was disturbed, they fluttered out 
and dropped into the water, and, to our astonishment, instantly 
vanished, but in a little time made their appearance at some distance 
down the stream, and it was with difficulty two out of five were taken, 
as they dived on being approached. The motion under water,” he 
says, ‘is effected by short jerks from the shoulder-joint, not, as in 
all other diving-birds, with extended wings.” 
Yarrell dissected this bird, and found nothing in its structure to 
account for its diving and remaining on the ground without any 
muscular effort. 
Mr. Macgillivray (Naturalist, vol. i. p. 105) says, “I have seen the 
Dipper moving under water in situations where I could observe it 
with certainty, and I readily perceived that its actions were similar 
to those of the Divers, Mergansers, and Cormorants, which I have 
often watched from an eminence as they pursued the shoals of sand- 
eels along the sandy shores of the Hebrides. It in fact flew, not 
merely using the wing from the carpal joint, but extending it con- 
siderably, and employing its whole extent as if moving im the air. 
The general direction of the body is obliquely downwards ; and great 
force is evidently used to counteract the effects of gravity, the bird 
finding it difficult to keep at the bottom.” 
Other observers have given similar testimony, some asserting that 
bubbles of air appeared on the surface after the bird was submerged : 
but these must have arisen from the disturbance of the earth at the 
bottom of the river; for no diving-bird, I believe, emits air from its 
lungs when under water. The air is got rid of before the act of 
diving takes place. But let me now speak of some parts of the 
anatomy of this bird, before I attempt to answer the first question. 
The average weight of this bird is said to be 2} oz. ; but in four that 
I have weighed the average weight has been about 23 oz., the males 
being a little heavier than the females; the length 73 inches, and 
11 inches from the tip of each wing. The brain weighed 10 grains, 
the eyes 12 grains, the skin and feathers 132 grains, the pectoral 
muscles 135 grains. The gizzard moderately thick, and lined with 
a tough cuticle. The length of the whole alimentary tube was 
16 inches; the cesophagus, as in the other Merulide, not dilated 
into a crop. The trachea of nearly uniform calibre, and consisting 
of 36 rings; the vocal muscles largely developed, as in the other 
members of this family. The tail-glands comparatively of large size. 
I have depicted all the above parts in the drawing before the 
Society ; but the parts of the anatomy of this bird to which I am 
. anxious to direct attention are the shortness of the wing and the great 
development of the wing-muscles—features which I believe will in 
