LEPUS. 385 
fast as they are worn away by use. Just behind the upper 
incisors is a pair of little peg-like second incisors. Behind 
the incisors is a part of the jaws with no teeth, forming a 
space or dastema, and further back is a row of six flat teeth 
on each side of each jaw. These are the molar teeth 
with flattened ridges which serve to crush and masticate 
the food (various vegetables). The cheeks can be pushed 
together across the diastema ; and in this way the incisors 
may be used on occasion for gnawing without the products 
passing into the cesophagus. 
This peculiar type of dentition is characteristic of the 
order Rodentia to which the rabbit belongs. 
The esophagus (see Plate XI.) passes down the neck as a 
soft tube and emerges through the diaphragm, opening into 
the large stomach towards the left side. The duodenum forms 
the usual loop, in which is a diffuse pancreas with a single 
pancreatic duct passing into the distal limb of the duodenum. 
The liver is very large and has five lobes. Partially em- 
bedded in it is the gadl-b/adder, from which there passes a 
bile-duct opening into the proximal limb of the duodenum. 
After the duodenum, the z/ewm forms an enormously long 
(8 feet) and coiled tube of small calibre. It terminates in 
the sacculus rotundus, a swollen sac which opens distally into 
the cecum. The cecum is a blind tube of large calibre which 
terminates in a small process, the vermiform appendix. It 
is continued, in the opposite direction, into the colon with 
sacculated walls and is about 18 inches long. It gradually 
loses its sacculation and passes into the rectum, a thin-walled 
tube about two feet long terminating in the anus. 
The large size of the caecum (about two feet long) and 
great length of the intestine are usually correlated with a 
herbivorous diet. . 
The duodenum and ileum are the two portions of the 
small intestine, the colon and rectum forming the “large 
intestine.” The sp/en is, as in other types, a dark-red body 
lying near the pancreas and beside the stomach. 
The portal vein, as in preceding types, should be noticed 
before removal of the alimentary canal. It is formed of a 
“ienogastric from the stomach and spleen, a duodenal and 
anterior and posterior mesenterics. The organs drained by 
the portal are supplied with arterial blood by the celiac, 
M. 26 
