494 MR. R. LYDEKKER ON SCELIDOTHERIUM. [ Nov. 16, 
The only other part of the skeleton to which I wish to call 
attention is the astragalus, and I have accordingly figured the type 
specimen in Plate XLIX. fig. 3. It will be seen from this figure that 
the external trochlear ridge for articulation with the tibia is not 
prominent, and scarcely projects above the level of the internal 
tuberosity. The astragalus (B.M. No. 37476) associated with the 
cranium No. 37308 exhibits precisely similar features, although it 
is of somewhat larger dimensions. This type of astragalus is very 
widely different from that of Megatherium (in which the external 
trochlear ridge is extremely prominent), and apparently indicates 
that the eversion of the foot was not so great as in that genus. 
ScELIDOTHERIUM BRAVARDI, 0. Sp. 
This species is founded on an imperfect skeleton in the British 
Museum, brought by Bravard from the Argentine Republic, which 
presents features clearly showing that it cannot belong to the type 
species, to which it has hitherto been referred. The cranium (B.M. 
No. 37626), which lacks the whole of the dentition and the greater 
portion of the nasals, has been figured by Sir R. Owen in the ‘ Philo- 
sophical Transactions’ for 1857, pl. viii. fig. 2, from the palatal 
aspect *, and referred to the type species ; an upper view is given in 
Plate XLVII. of the present memoir. It is extremely unfortunate 
that the nasals are wanting ; but from the structure of the adjacent 
bones it can be shown that these bones were certainly much shorter 
than in S. leptocephalum, since in the first place the superior border 
of the facial portion of the maxilla forms a much shorter curve than 
in the latter, while if the nasals were of the same length as in that 
species they would have projected far in advance of the premaxille. 
That the nasals were of a shorter type is also evident from a com- 
parison of the figure with that of S. chiliense (Plate XLVIII.), when 
it will be seen that the facial portion of the maxilla is not dissimilar 
in the two species. The whole cranium is, moreover, relatively 
narrower than in S. leptocephalum, and the frontal profile is quite 
straight ; while only a narrow moiety of the facial portion of the 
maxilla appears on the frontal aspect ; and the lachrymal is charac- 
terized by its extreme prominence, and the partially upward direction 
of the aperture of its canal. The anterior border of the zygomatic 
process of the maxilla is nearly vertical, while the fronto-parietal 
ridges are closely approximated, and the interdental portion of the 
palate (as is well shown in Sir R. Owen’s figure) is of excessive 
narrowness. It will also be seen from the following table of dimen- 
sions that while the width of the occipital condyles is smaller than 
in S. leptocephalum, the interval between the condyles and the last 
tooth is considerably greater, which indicates a great difference in 
the relative proportions of the two crania. The premaxille are well 
developed. 
In the mandible * associated with the cranium, while the length of 
1 The teeth have been introduced on one side in this figure. 
2 This specimen is figured by Owen, op. eit. pl. viii. figs. 4, 5, with the teeth 
restored ; and apparently in pl. ix. figs. 2, 3, the specimen represented in fig. 2 
being erroneously described as belonging to the upper jaw. 
