i8o 



EXTINCT XENARTHKA 



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 



FIG. 105. Mylodon robiistus. (Restoration, after Owen. 



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, Scelidotherium 

 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. 1 



1 Dr. Moreno and Mr. A. Smith Woodward in Proc. ZooL Soc. 1899, p. 144 ; 

 Wiss. Ergeb. Schwed. Exped. Magellansldnd. ii. 1899, p. 149. 



