THE DENTITION OF THE EA.BBIT. 441 



is a very large and completely exposed flocculus, and the 

 vermis is large in proportion to the lateral lobes of the 

 cerebellum. The corpora trapezoidea are well marked. 



The membrana nictitans is very large, has a convex free 

 edge, and contains a triangular cartilage. There are no 

 ptmda lachrymalia, but a crescentic aperture leads into the 

 lachrymal canal. The large lachrymal gland lies above and 

 external to the eyeball, and there is a well-developed 

 Harderian gland on its lower and inner side. 



The dental formula is i. - — - c. -^ p.m. —- m. —- = 28. 



The lower, and the inner upper, incisors are very large and 

 long; they grow continuously from persistent pulps, and they 

 are coated with enamel only in front, so that wear keeps 

 them constantly sharp. The second pair of small incisors 

 exists only in the upper jaw. A great diastema separates 

 the incisors from the first premolar above and below. The 

 grindiag teeth all grow from persistent pulps, and do not 

 form fangs; they have transversely ridged crowns, the 

 patterns of which are very similar throughout, the first and 

 the last only presenting some differences. The young 

 Rabbit has three incisors and three milk molars on each 

 side, in the upper jaw. In the lower jaw, there are only 

 two milk molars on each side. 



The stomach is simple, and there is a large ccecum. 

 Special glands pour their secretions at the side of the anus. 



The pancreas is very large, and its duct enters the in- 

 testine nearly a foot from the pylorus, and fa]' distant 

 from the biliary duct. 



There are two anterior cavse ; and the external jugular vein 

 is very much larger than the internal. 



In the male, the inguinal canal remains permanently 

 open, and there is a large uterus mascuHnus. In the female, 

 the uteri are quite sepai'ate, and each opens by a distract 

 OS tincce into the vagina. 



The distribiition of the Rodentia is almost world-wide, 

 Madagascar being the only considerable island in which 

 indigenous Rodents are unknown. The Austro-Colum- 



k 



