in the Mu$eum of Buenos Ayres. 87 



figure and those of the periphery is little or nothing : all the 

 hexagons of this central part of the shell are of equal siz» 



Also the tubercles of the edge of the shell are sroaUer and 

 different in shape ; these tubercles have, in G. ciavipes, a low 

 conical elevation on the external surface, which is wanting in 

 G. spinicaudus. In this species are seen about sixteen tubercles 

 at the posterior edge of the shell over the tail, and about twelve 

 on the anterior edge over the head. The lateral tubercles are 

 almost wholly wanting, and for this reason I do not know its 

 exact shape ; only, upon the shoulders, these large conical tu- 

 bercles may be seen to be a httle curved above, and arc of the 

 ■ame sort as those of which we have before spoken. 



The head bore also on its superior part a shell of plates much 

 smaller and irregular, but of the same construction as those of 

 the shell. It is not in my power to describe it in detail, in 

 consequence of that which we have in the Museum being broken. 

 The same applies to the feet — without doubt well armed with 

 plates like those of the living Armadillo, and having at the cud 

 of the toes large claws, of which there are four long ones on the 

 anterior and five wide ones on the poaterior extremities. There 

 arc a great quantity of small plates, veiy diverse in form and 

 size, preserved in the Museum, which snow by their construc- 

 tion that they were derived from the same skin. These plates 

 probably belong to the feet and to some of the small joints, 

 where the existing Armadillos have equally small plates, of 

 partly formed shell. 



The second species from the Buenos Ayres soil is G. elav^Des, 

 of which there exist in the Museum an imperfect shell and two 

 tails. Undoubtedly it is larger than the first, although, as it is 

 broken, we are not exactly aware of its dimensions ; but the 

 larger size of this animal is not alone demonstrated by the greater 

 size of the loose plates of the shell, but by that of the bones of 

 the skeleton which we have in the Museum. At the same time, 

 it appears to me much more narrow and elongated than G. spi- 

 mcaudus. The specific difference is very clear in the side plates 

 of the shell, — the central hexagon being larger than the peri- 

 pheral hexagons, and the structure of the surface being finer, less 

 elevated, and less rough. The tubercles of the edge of the shell 

 appear less convex, and the centre of the external superficies is 

 a little elevated, as we have said above, compared with the tu- 

 bercles of G. ^inicmuhu. 



But the most distinguishable character of this species is the 

 existence of a peculiar semicircular border below the tubercles 

 of the edge, covered with rhomboid figures. This border does 

 not exist in Glyptodon spinicaudus. The tail is very different, 

 being long, thin, almost cylindrical, with some rings at its base 



