TEE DIGESTIVE APPARATUS OF BIRDS. 511 



Nothing is to be said of its structure, and the arraugeiBent of its excretory apparatus is 

 identical with that of the Ox. 



On the lower face of the right lobe are three depressions: au anterior or impressw colica; a 

 deep middle one, impressio vesicse ; and a small posterior one, which receives the supra-renal 

 capsules, impressio renalis. 



2. Pancreas.— This organ is very elongated transversely, like that of the Dog and Cat. It 

 is closely applied against the lumbar vertebrae, as in the Horse, bijt its anterior face is much 

 more enveloped by the peritoneum. Its right extremity rests on the duodenum, while the left 

 corresponds to the spleen and left kidney. Its texture is consistent, and of a greyish-white 

 colour. The duct of Wirsung terminates, along with the ductus choledochus, in the ampulla 

 of Vater. 



3. Spleen. — This is not falciform, but quadrangular ; its inferior extremity is larger than 

 the superior. It is attached to the stomach by the great omentum, and its inner face is divided 

 into two portions by a salient ridge ; a little in front of this is a fissure — the hilum lienit — 

 by which vessels enter it. 



CHAPTEK III. 



The Digestive Apparatus of Birds. 



Constructed on the same plan as that of Mammals, the digestive apparatus of 

 Birds nevertheless offers in its arrangement several important peculiarities, 

 which will be hurriedly noticed in reviewing, from the mouth to the anus, its 

 different sections. 



Mouth. — The essentially distinctive character of the mouth of Birds consists 

 in the absence of lips and teeth, these organs being replaced by a horny production 

 fixed to each jaw, and forming the salient part termed the heak. In the Gallinam^ 

 the beak is short, pointed, thick, and strong, the upper mandible being curved 

 over the lower. In Palmipeds, it is longer, weaker, flattened above and below, 

 widened at its free extremity, and furnished within the mouth, on the borders of 

 each mandible, with a series of thin and sharp transverse laminae to cut the 

 herbage. 



The muscular appendage, or tongue, lodged in the buccal cavity, is suspended 

 to a remarkably mobile hyoidean apparatus. Covered by a horny epithelium, 

 and provided at its base with several papillae directed backwards, this organ 

 always affects the form of the lower jaw : in Poultry it is like the barbed head 

 of an arrow, the point being directed forwards ; in Pigeons this saggital form 

 is still more marked : in Geese and Ducks, on the contrary, and in consequence 

 of the wide shape of the beak, it has not this disposition, and is softer and more 

 flexible than in the GalKnacse, 



With regard to the salivary glands annexed to the mouth, they are imperfectly 

 developed, the presence of the fluids they secrete being less necessary in Birds 

 than in Mammals, as the food is nearly always swallowed without undergoing 

 mastication ; consequently insaUvation is all but useless. 



Gurlt ^ speaks of a parotid gland situated beneath the zygomatic arch, the duct 

 of which opens into the mouth behind the commissm-e of the jaws. Meckel names 

 this organ the angular gland of the mouth, and says that it is difficult to regard it 



' GturM, Anatomie der Hausyogel. Berlin: 1849. 



