180 EXTINCT XZWVARTHRA CHAP. 
form of scattered plates, small and not fused together. The 
general aspect of the skull is decidedly Sloth-like. As in that 
animal, the malar bone is bifid posteriorly, and between the 
bifurcation is embraced the process of the squamosal. This latter 
is thus more de- 
veloped than in the 
Sloth, but there is 
no actual union be- 
tween it and the 
malar. The pre- 
maxilla is small. 
The lower jaw has 
both coronoid and 
ascending processes, 
and is massive. 
There are five teeth 
on each side above, 
and four on each 
side below, as in the 
Sloths. There are 
the normal seven 
cervical vertebrae and sixteen dorsals. The limbs are not long and 
slender, but short and strong, the animal having been terrestrial. The 
fore-feet were five-toed, of which the three inner toes had claws. The 
hind-feet were only four-toed, and the two inner only were clawed. 
Scelidotherium is a genus which is a trifle smaller than the 
last. It has only four properly-developed toes in the fore-foot, 
the thumb being rudimentary ; of these, the first two bear claws. 
The hind-feet are also four-toed. Like Mylodon, Scelidotheriwm 
is a Pleistocene genus. 
Glossotherium has a skull very much like the last two 
genera ; but it is remarkable for the fact that the nostrils instead 
of being unprotected with bone anteriorly are there closed by a 
plate of bone formed by the well-developed premaxillae, the 
nostrils appearing at the sides, and giving the skull a curious 
likeness to that of a Chelonian. From a series of recent and 
most important observations it appears to be clear that this genus 
has survived into quite modern times.’ 
Fic. 105.—Mylodon robustus. (Restoration, after Owen.) 
1 Dr. Moreno and Mr. A. Smith Woodward in Proc. Zool. Soc. 1899, p. 144 ; 
Wiss. Ergeb. Schwed. Exped. Magellansland. li. 1899, p. 149. 
