776 MR. W. N, HARKKR ON THE INDIAN TAPIR. [DeC. 1 9> 



Tapir, evidently older than the above. This shows exactly the same 

 thing — -the last milk-molars still in place and much worn, the cor- 

 responding premolars in their sockets in the jaw, and the first true 

 molars above and below in place, the last two (sixth and seventh 

 above, and fifth and sixth below) not having yet come into use. 



Prof. Flower has shown me a series of Tapir's skulls in the Col- 

 lege of Surgeons' Museum, in which the different stages of the first 

 premolar can be seen, up to the time at which it takes its place 

 amongst the others. 



Comparing the patterns of the milk-teeth with the permanent 

 ones, they, with the exception of the first, are seen to resemble one 

 another very closely. The inner cusp of the first deciduous molar 

 is much larger than in its successor, and thus more nearly resembles 

 the pattern of the other grinders ; moreover, both upper and lower 

 first milk-molars are considerably larger than their successors (see 

 Plate LIX. figs. 5-8). The outer incisiors in both jaws are rela- 

 tively not so large as in the adult, being only about the same size 

 as the inner and middle ones ; the canines also are relatively smaller. 



In the skeleton I have only a few remarks to make on certain 

 parts of the skull and on the pelvis. 



The tympanic bone, with the external meatus, is small, and does 

 not become ankylosed to the surrounding parts ; so that it is rarely seen 

 in dry skulls. Between the tympanic and periotic, on the lower side, 

 is a flat, somewhat curved fibro-cartilage (Plate LIX. fig. 9, ty'), 

 which passes posteriorly into a mass of fibrous tissue, in which is 

 imbedded a very definite os bullae (o.b), similar to those which exist 

 in the Pig ', Bat, &c., except that in these animals there are more 

 than one. The fibro-cartilage is the homologue of that part of the 

 tympanic which, in such mammals as the Carnivora, becomes ossified 

 separately to form the bulla^ ; and the os bullae corresponds roughly 

 to this ossification. In these mammals the tympanic ossifies by two 

 centres, one forming the outer part, and giving rise to the external 

 meatus and to the region which gives attachment to the membrana 

 tympani, and the other forming the bulla. These two parts even- 

 tually completely fuse together. Thus in the Tapir, Pig, and Bat 

 only the outer ossification becomes of any physiological importance, 

 the inner one remaining in a rudimentary condition. 



The stapes is elongated, as in other Ungulates ; and there is a 

 distinct interhyal cartilaginous nodule imbedded in the tendon of 

 the stapedius muscle. 



Above the pterygoid proper there is a separate mesopterygoid 

 centre in the form of a thin scale of bone on each side. This is 

 common in Marsupials, and exists also in the Fox and Pig'. 



In the pelvis there was a small separate ossification on the upper 



' See W. K. Parker, " On the Structure and Development of the Skull in the 

 Pig," Phil. Trans. 1874. 



^ See Prof. Flower, " On tlie Value of the Cliaracters of the Base of tlie Cra- 

 nium in the Classifieation of the order Carnivora," P. Z. S. 18(J9, pp. 15-17. 



a Vf. W. K. Parker, loc. clt. p. 32-1. 



