i8o 



EXTINCT XENARTHRA 



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 

 tSloth, but there is 

 no actual union be- 

 tween it and the 

 malar. The p re- 

 maxilla is small. 

 The lower jaw has 

 ]»oth coronoid and 

 ascending processes, 

 and is massive. 

 There are five teeth 

 on each side above, 

 and fom- on each 

 side below, as in* the 

 .Sloths. There are 

 the normal seven 

 cervical vertel^rae aiid sixteen dorsals. The limits are not long and 

 slender, but short and strong, the animal having Iteen terrestrial. The 

 fore-feet were five-toed, of wiiich the three inner toes had claws. The 

 hind-feet were only fom:-toed, and the two iimer only were clawed. 

 ScclidotJirrium is a genus which is a trifle smaller than the 

 last. It has only fom' 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, Scclidotlicrium 

 is a Pleistocene genus. 



Glossotlicrium has a skull very much like the last two 

 genera ; 1 )ut 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 Ijy the well -developed premaxillae, the 

 nostrils appearing at the sides, and giving the skull a ciu:ious 

 likeness to that of a Cheloniau. From a series of recent and 

 most important observations it appears to be clear that this genus 

 has survived into quite modern times.^ 



^ Dr. Moreno and Mr. A. Smith Woodward in Proe. Zool. Soc. 1899, p. 144 ; 

 jriss. Ergch. Schivcd. Exj^ed. Magellansland. ii. 1899, p. 149. 



Fig. 105. — Mijloduii rolm^tics. (Restoration, after Owen.) 



