SPLANCHNOLOGY 153 



fluids containing ferments which aid in splitting or digesting the 

 food. 



The Liver (Figs. 31, 33 and 34). Location. The liver, hepar, 

 lies ventrally and posteriorly to the heart. It is related anteriorly 

 with the diaphragm, inferiorly with the sternum, posteriorly with 

 the gizzard and intestine, and superiorly with the ovary, oviduct 

 and proventriculus and laterally with the abdominal wall. 



Shape. The liver is a voluminous deep livid brown gland, soft 

 and friable in texture. It is divided into two principal lobes, a 

 right and a left. 



The right lobe is larger than the left. In the hen of average size 

 the liver weighs 35 grams. The parietal surface is convex and 

 'smooth. The surface which lies against the viscera is irregularly 

 concave. The visceral surface furnishes exit for the bile duct and 

 passage for the nerves and blood-vessels. This part is called the 

 porta. 



The left lobe may be cleft from below so deeply as to form two 

 lobes on that side. 



Structure. Each lobe is covered by a double serous membrane, 

 one closely adherent, the other surrounding the structure loosely. 

 These tunics, which are reflections of the peritoneum, are continued 

 from the base of the liver, over both the anterior, and the posterior 

 surface. The loose layer is formed by the air cells surrounding the 

 lobes. The thin border of the liver is usually free. 



The two lobes of the liver are connected by a narrow isthmus of 

 liver tissue. Occasionally there is a bird in which there occurs a 

 lobus Spigelii located at the posterior of the liver between the two 

 principal lobes. 



The apex of the heart sacculates the diaphragm backward, so that 

 part of this apex lies between the right and the left lobes (Fig. 

 43, No. 6 and 7). A ligament, the falciform, extends from the apex 

 of the pericardial membrane, and attaching it rather firmly to the 

 central connective tissue, or interlobar ligament. This ligament 

 also has attachments to the inner surface of the sternum. The 

 broad ligament of the liver is formed posteriorly by a fold of the 

 peritoneum. 



The interlobar, or principal, ligament of the liver is formed by a 

 large and strong duplicature of the peritoneum, which makes a 

 longitudinal division in the abdominal cavity similar to the lateral 

 division made by the thoracic mediastinum in mammals. It 



