776 MR. W. N. PARKER ON THE INDIAN TAPIR. _ [ Dec. 19; 
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 bullze (0.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 bullz 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 the Value of the Characters of the Base of the Cra- 
nium in the Classification of the order Carnivora,” P. Z. 8. 1869, pp. 15-17. 
3 Uf. W. K. Parker, loc. cit. p. 324. 
