294 THE ALIMENTARY TRACT, ETC. 



(6) The blood-vessels (Fig-. 193) have a simple arrang-ement. 

 The arteries are large^, and form oblique loops around the intestine^ 

 lying under the peritoneum ; from these branches are given off to 

 form a series of rings in the submucous membrane (Fig. 193 A) ; 

 from these fine twigs are given off to form a fine anastomosis under 

 the mucous membrane (£). 



(7) The lymphatics of the large intestine are arranged in two 

 chief systems : one under the serous coat resembles the corresponding 

 system of the small intestine. The second set forms a network of 

 rounded loops in the submucous coat, which give rise to a secondary 

 set of smaller vessels towards the mucous membrane ; this secondary 

 system forms a sort of trellis-work standing on the rounded loops, 

 and so maps out small blocks of the thick submucous coat. Towards 

 the cloaca the arrangement is simpler ; the secondary lymphatics 

 are lost, while the primary lymphatics tend to form elongated, 

 longitudinal loops (Langer).] 



II. THE GLANDS CONNECTED WITH THE 

 INTESTINAL CANAL. 



A. The Liver and Gall-bladder, 

 a. External form. 



(i) The liver (Figs. 185, 194) is a large, reddish -brown organ, 

 occupying a large part of the anterior abdominal region. It con- 

 sists of three or more lobes, which present many individual varia- 

 tions ; as a rule there are two larger lateral lobes [L and L^), and 

 a smaller median lobe (L'^). Each lobe has a superficial or ventral 

 surface, which is convex, and a deep or dorsal surface, which is con- 

 cave and directed towards the other abdominal viscera lying above 

 the liver. The two surfaces of each lobe meet to form a sharp 

 border around the lobe, except where the three lobes are more 

 intimately attached, opposite the apex of the heart (Figs. 185, 

 1 94) ; at this place each lobe possesses a small, flat, or slightly 

 concave anterior surface. 



The left lobe (L) hides the greater portion of the stomach, and 

 has near its inner border a deep fissure, which rvms forwards and 



