COMMON RAT. 263 



thirdly, the fourth lobe of the right lung within its own pleural cavity, 

 in relation with which is the phrenic nerve ; and, lastly, the lobules of 

 fatty tissue, already spoken of, in apposition with the fourth and fifth 

 of the six sternal bones. 



q. Left, azygos vein joining the vena cava superior of the same side, and 

 receiving some veins from the masses of fat just mentioned in connec- 

 tion with the pericardium. 



r. Root of left lung : the lung of this side has been removed ; it consisted 

 of a single lobe, as is often, though not always, the case in Rodentia, 

 Marsupialia, and Insectivora, though very rarely in Carnivora and 

 Quadrumana ; see Cuvier, Leons d' Anatomic Comparee, torn. vii. ed. 

 2 nde , 1840, pp. 156-163. 



s. Kidney. 



t. Spleen. 



u. Stomach. 



v. Liver ; the line abutting upon its left lobe. 

 w. Omentum or epiploon. 



x. Coecum. The entrance of the small intestine into the coecum is not 

 seen, but we observe that the coecum becomes smaller in calibre where 

 it is bent on itself superiorly. 



x. Convolutions of intestines. 



y. Upper end of left cornu of pregnant uterus, passing into the Fallopian 

 tube, which together with the ovary fills up the space between this 

 convolution of the uterus and the kidney. 



y f . Lower portion of same uterine cornu distended with foetuses. 



2. Bladder contracted into a conical shape and receiving the ureter at its 

 base on the left side. 



z'. Outlet of urinary organs through a perforated clitoris distinct from the 

 vagina. 



IT. Rectum. 



A. Flexor muscles of the tail, which arise from the internal surface of the 

 pelvic bones. 



b. Anterior portion of ilium, the posterior part of which has been removed, 

 together with the pubis and ischium. From its internal surface the 

 caudal flexors are seen to take origin, and in front of them and in a 

 line with the point on which the letter 8 is placed, the cut end of one 

 of the great veins returning blood from the hind limb is seen. 



