1886. ] MR. R. LYDEKKER ON SCELIDOTHERIUM. 495 
the symphysis is greater than in S. leptocephalum, the interval 
between the hinder border of the symphysis and the first tooth is 
very considerably less. The superior border of that portion of the 
mandible in advance of the teeth is moreover inclined strongly 
upwards. 
The following dimensions may be compared with those of S. 
leptocephalum :— 
Length of facial part of maxilla (about) ....-.--- 0°135 
Width of the two occipital condyles .........+.. 0°095 
Length from condyle to last tooth...........+.- 0°258 
Length of upper dental series ........-..++--: 0°105 
Length of mandibular symphysis ............+: 0°175 
Interval between hinder border of symphysis and 
BENNER, Fe wade BST bios io ryel har ney g SEE PHE DS 0°350 
Interval between do. and first tooth ...........- 0°032 
I will now direct attention to the astragalus. Unfortunately the 
one specimen of this bone, associated with the cranium, is imperfect, 
although sufficient remains to show that it differs from the corre- 
sponding bone of the type species by the great prominence of the 
external trochlear ridge, which projects far above the level of the 
internal tuberosity. In Plate XLIX. fig. 4, there is represented an 
astragalus from a cavern in Brazil, which, although of larger size 
than Bravard’s specimen, agrees precisely in structure, and either 
belongs to a male of the present form or to an allied species ; and I 
think a comparison of this figure with that of the astragalus of 
8. leptocephalum will leave no doubt as to the specific distinctness 
of the two forms. This astragalus agrees precisely with the corre- 
sponding bone of a hind foot belonging to a perfect skeleton figured 
by Dr. Burmeister in the Monatsb. k. preuss. Ak. Wiss. for 1881, 
plate facing p. 380, fig. 2, and referred (on the authority of Sir R. 
Owen’s figure of the cranium of the present form) to a large male 
of S. leptocephalum. A tibia from Brazil, associated with the 
figured astragalus, presents a structure of its distal surface modified 
to accord with this peculiar articulation, which is different from that 
of the tibia of S. leptocephalum ; and there are equally well-marked 
differences in some of the other bones of the present form to which 
I shall allude on another occasion. 
Whether or no the larger bones mentioned above belong to male 
individuals of the same species as the cranium, I think sufficient 
evidence has been adduced to show that both the form to which 
the latter and that to which the former belonged are specifically 
distinct from S. leptocephalum. 
Confining, however, attention to Bravard’s specimen, it is quite 
evident that this form is distinct both from S. tarijense (in which 
the mandible is of quite a different type) and S. (Platyonyx) brong- 
niarti (in which the nasals are very short and the premaxille 
aborted) ; and since it appears impossible to identify it with either 
of the ill-defined Brazilian forms mentioned above to which specific 
names have been assigned, I propose that it should be known as 
