1898.] ANATOMY or PEDETES CAPFBR. 859 



strongly flexed, while the most comfortable position of the ankle 

 seems to be one of extreme dorsal flexion, so that the dorsal surface 

 of the foot is in contact with the shin as far as the heads of the 

 metatarsal bones. There are four toes in the foot, the hallux being 

 absent and the most fibular toe the smallest ; they are provided 

 with strong triangular claws compressed from above downward. 

 The second toe from the tibial side is the largest. 



The vagina and rectum open by a common aperture 2 inches 

 below the root of the tail; it is soon divided into a smaller rectal 

 part and a larger vaginal. On each side of the vulval orifice is a 

 crypt about g inch deep, and this leads by a wide orifice into a 

 thick-walled, almond-shaped sac g inch long. When this sac is 

 opened up, it is seen that at the orifice the mucous membrane has 

 longitudinal rugae, but that nearer the fundus it is covered with 

 hairs about g inch long. The walls are evidently glandular and 

 the cavity contained a quantity of inspissated secretion '. 



On comparing the external anatomy of Pedetes with that of Dijnis 

 one is struck by the general resemblance between the two ; there is 

 the same breadth at the back of the head, and want of proportion 

 between the fore and bind limbs ; in Dhpus, however, the upper lip 

 is divided and the white upper incisors are grooved as they are in 

 the embryo of Pedetes. There are four pairs of nipples instead of 

 two as in Pedetes ; the most anterior pair are situated at the root 

 of the neck, and the most posterior almost opposite the vulval 

 orifice. 



In the hand the claws closely resemble those of Pedetes., but that 

 on the poUex is quite short. As in Pedetes there are two prominent 

 projections in the palm; of these the radial is the better developed, 

 but no nail is present. 



In the hind foot there are only three toes, and the claws are 

 more laterally compressed than those of Pedetes. 



The Osseous System. 



As the osteology of Pedetes is well known and several skeletons 

 of it exist, I shall only make a brief survey of the bones of the 

 specimen in my possession, comparing them with those of the 

 foetus and of Bipus jaculus. 



The dorsal surface of the skull is remarkable for the strength 

 and breadth of the nasals ; the frontals too are very large, in the 

 median line they are twice as long from before backward as the 

 parietals, while in Dipus the parietals and frontals are of the same 

 length. The interparietal only projects for a short distance 

 between the parietals ; in the foetal Pedetes the interparietal is 

 much larger than the adjacent supraoccipital. In the lateral view 

 the infraorbital foramen is deeper in Pedetes than in Dipus, and in 

 the latter animal there is a small separate foramen below through 

 which the infraorbital nerve makes its exit. 



1 The external anatomy of the foetal specimen will be found with the 

 description of the uterus. 



57* 



