246 



DIGESTION. 



glands occupy in relation to the larger salivary glands, the" 

 parotid, and submaxillary. 



The Villi (Figs. 81, 82) are confined exclusively to the mu- 

 cous membrane of the small intestine. They are minute vas- 

 cular processes, from a quarter of a line to a line arid two-thirds 

 in length, covering the surface of the mucous membrane, and 

 giving it a peculiar velvety, fleecy appearance. Krauss esti- 



FIG. 81. 



(Slightly altered from Teiehmann.) A. Villus of sheep. B. Villi of man. 



mates them at fifty to ninety in number in a square line, at 

 the upper part of the small intestine, and at forty to seventy 

 in the same area at the lower part. They vary in form even 

 in the same animal, and differ according as the lymphatic ves- 

 sels they contain are empty or full of chyle; being usually, in 

 the former case, flat and pointed at their summits, in the latter 

 cylindrical or clavate. 



Each villus consists of a small projection of mucous mem- 

 brane, and its interior is therefore supported throughout by 



