486 



ANATOMY OF VERTEBRATES. 



divided into two, the right division being the smallest. The part 

 answering to the cystic lobe is deeply cleft into three subequal 

 lobules, between the two right of which, at the base of the cleft, 

 lies the long pyriform gall-bladder. The homologue of the left 

 lobe is of a broad and rounded figure : it is attached by a band of 

 hepatic substance, one inch broad, to the base of the 'cystic lobe, 

 this band bridging over the portal vessels. The lobulus Spigelii, 

 so constant in its position behind the small omentum in Mammals, 

 here forms the seventh portion of the liver. The gall-bladder is 

 three and a half inches long, and one and a half inch in diameter: 

 a duplicature of peritoneum, one inch broad, extends from the 

 cervix vesica3 and the cystic duct to the duodenum. The fundus 

 of the bladder is attached by shorter folds of peritoneum to the 

 two walls of the cystic fissure ; it has an entire serous investment. 

 The liver of the Seal (Phoca vitulina) differs chiefly in the 

 greater elongation and more pointed form of its divisions : viewed 

 from below or behind, the left lobe, fig. 370, a, retains most of 



the normal shape ; in 

 the cystic lobe, b, />, 

 the suspensory fissure 

 is marked by the round 

 ligament, c, the cystic 

 one, d, by the gall- 

 bladder, e ; f is the 

 larger, and q the 



o / 



smaller divisions of 

 the right lobe, h being 

 the Spigelian lobule 

 or process ; /is the 

 portal vein entering 

 the fissure so called ; 

 h is the post-caval, 

 perforating the liver 

 to combine with the 

 hepatic veins in form- 

 ing the capacious sinus, /, /, trom which the trunk, again con- 

 tracted, m, is continued to perforate the diaphragm, before termi- 

 nating in the heart, The hepatic veins in the Seal have an outer 

 coat of circular fibres. 1 The accumulation of blood in the sinus 

 of the hepatic veins during the act of diving indicates the need 

 of a muscular power to propel the blood onward to the heart. 

 The under surface of most of the lobes shows small notches or 



1 CLVII". p. 738, pi. xxiii, fig. 2. 



Liver of S< al, from Inland. 



