STRUCTURE OF BIRDS. 63 



kind of valve or thickened rim. The ureters, d., d, are seen 

 opening upon a prominence at e, below which is the larger 

 orifice of the Fabrician bursa. 



The functions are as described with reference to the Peregrine 

 Falcon. The Snowy Owl is essentially a rapacious bird, and 

 is organized for seizing live animals of various kinds, which it 

 kills by thrusting into them its long, curved, tapering, extreme- 

 ly acute claws. After tearing off the feathers and hair in a 

 partial manner, it tears up the flesh with its hooked and sharp- 

 edged bill, and swallows it in fragments, until it has filled not 

 only the stomach, but also the oesophagus, w^hich, although not 

 dilated into a crop, is yet wide throughout, and capable of con- 

 taining a large quantity. The food is gradually dissolved in 

 the stomach by the action of the proventricular fluid, and the 

 feathers, hair, bones, scales of fishes, and other indigestible sub- 

 stances, ejected in pellets. The changes already described take 

 place as the chyme descends ; but, as the intestine is, for some 

 unknown reason, comparatively short, the alimentary mass 

 passes into the coeca, where it undergoes a further elaboration 

 and absorption. The refuse at length enters the rectum, and 

 accumulates in the cloaca, where it is farther diluted by the 

 urine, and whence it is finally ejected at once, and cast to a con- 

 siderable distance. 



The length of a male Snowy Owl, from the point of the bill 



to the end of the tail, is 23 inches. 



Length from the point of the bill to the end of the 



rump, 14 V 



Tongue, i^ 



(Esophagus, 9 

 Intestine, .,.S8 



— Intestinal canal, 48 '/ 



The intestinal canal is therefore to the whole length as 2.086 

 to 1 ; and to the length of the body, without the feathers, as 

 3.428 to 1. But if the two coeca are added, the proportional 

 length of the canal is considerably greater. 



Now, the points in which the digestive organs of the Pere- 



