54 



CHAPTER III. 



THE VISCERA, AND VASCULAR SYSTEM. 



The Viscera. 



In the female tlie body cavity consists of three parts : a main central cavity, and 

 two extensions or diverticula opening out of it. The central cavity is situated 

 immediately behind the gill region and beneath the ten anterior vertebrae, and extends 

 back to the anterior ventral interspinous bone. The two diverticula extend backwards 

 from the main cavity, one on each side of the median skeletal partition of the body 

 along the ventral edge. These lateral cavities extend from a little behind the anus 

 to -jtli the length of the body from the tail, getting narrower dorso-ventrally towards 

 the posterior end. The median anterior cavity contains the stomach and part of the 

 intestine, the liver, and the spleen {see Plate VIII, 1 ). The right lateral cavity is the 

 larger, and contains four parallel sections of the alimentary canal, also the right ovary. 

 The left cavity contains only the left ovary and a part of the left kidney, which projects 

 into it. 



The liver is shaped like a flat cake with one surface smooth and the other made 

 irregular by the entrance of blood vessels, &c. The greater part of this smooth 

 surface is turned to the left, and occupies neai^ly the whole dorso-veutral extent of 

 the main body cavity ; it is the only thing seen in that body cavity on removing the 

 left body wall. But the liver is doubled on itself anteriorly so that a smaller portion 

 of the smooth surface lies beneath the body wall of the right side in the anterior 

 part of the body cavity. 



Projecting from beyond this surface towards. the dorsal boundary of the body cavity 

 on the right side is seen the gall bladder, which is spherical. The liver is attached to 

 the anterior wall of the body cavity by a short ligament, situated in the median line 

 towards the dorsal limit of the anterior wall, about 1 cm. long at its peritoneal 

 attachment, and 3 mm. at its hepatic. 



The oesophagus passes into the main body cavity at its dorso-anterior angle, dorsal 

 to the liver, then with a very slight dilatation to form the stomach it passes backwards 

 enveloped between the two parts of the liver, then following the boundary of the 



