132 EQUINE ANATOMY. 



SPLEEN. 



This is not properly an annexed gland of digestion, but from 

 its position it is discussed in this section. It has no duct and is 

 therefore, a ductless gland. 



It is situated in the diaphragmatic and left hypochondriac 

 regions, and suspended from the sub-lumbar. Its shape is falci- 

 form, and directed downward and backward. 



Weight, thirty-two ounces. 



It has an external convex face, an internal concave, a convex 

 posterior and concave and sharp anterior border, a base or superior 

 extremity, and a point or inferior extremity. 



Ligaments. 



Suspensory, from sub-lumbar region and left kidney to base. 

 Gastro-splenic omentum, a process of peritoneum enveloping 

 whole organ except at anterior fissure. 



Structure. 



Serous coat, from peritoneum, most external. 



Fibrous coat, thick and strong, sending prolongations or trabec- 

 ulae into the interior which support the splenic pulp. 



Splenic pulp, reddish material which fills the interior of the 

 organ; composed of pigment, broken down corpuscles, etc. 



Malpighian corpuscles, small rounded bodies of lymphoid 

 structure enveloped by the outer tunic of the small arteries. They 

 are large in well fed, and small in starved animals. 



Vessels . Splen ic . 

 Nerves. Solar plexus. 



THE PERITONEUM. 



The peritoneum is a serous membrane with a visceral and 

 parietal layer, and enveloping nearly all the organs of the abdom- 

 inal cavity more or less completely. 



Beginning at liver it forms the ligaments already described, a 

 fold, the gastro-hepatic omentum, which separates, to enclose the 

 stomach, and sending reflections to the duodenum and caecum on 

 the right, and the spleen on the left, forming the gastro-splenic 

 omentum. Its median portion descends in front of the intestines, 

 having a large amount of fat developed in its structure, the great 



