520 Geological Society. 



Armadillos, the weight of the cuirass is transferred from the sacrum 

 to the thigh-bones by two points on each side. One of them, the 

 ischium, is anchylosed to the posterior part of the sacrum, the other 

 point is formed hy the conversion of the iliac bone into a stout three- 

 sided beam passing straight from the thigh-joint to abut against 

 the anterior part of the sacrum, where the weight of the shell is 

 greatest, — a structure which is wanting in the Megathere. In no 

 species of Armadillo is the ilium expanded, while in the Megathere 

 it is greatly developed, resembling that of the Elephant in size, form, 

 and position ; and among the Edentata the nearest approach in this 

 portion of the skeleton is to be found among the Sloths and Ant-eaters. 

 The most striking point however, in the structure of the Armadillos, 

 with reference to the support of a bony covering, is the remarkable 

 production of a part of the vertebra from above the anterior articular 

 process on each side, in a straight direction upwards, outwards, and 

 forwards, to nearly the height of the true spinous processes. Now, 

 these oblique processes, which are developed only in the loricated 

 Edentata, beautifully correspond in form and use with the tie-bearers 

 in the architecture of a roof, and are entirely wanting in the Me- 

 gathere, the structure of this part of the vertebral column of that 

 animal corresponding with the character of the vertebrje of the hair- 

 clad Sloths and Ant-eaters. Mr. Owen noticed other supposed adap- 

 tations in the skeleton of the Megathere to sustain a bony covering, 

 as the breadth of the ribs, but the ribs of the Sloths and Ant-eaters 

 are broader than those of the Armadillos. 



The paper contained a tabular account of the discovery of twelve 

 skeletons of the Megathere, and in no instance did any portion of 

 bony armour occur with or near the bones. A notice was also given 

 of the remains of a Glyptodon, found in the left bank of the Pedernal 

 before its junction with the Sala, an affluent of the Rio Sante, near 

 Monte Video, and preserved in the museum of that town. From 

 the accounts which have been given of these remains they appear to 

 have belonged to the same species as that described in the paper. 

 An allusion was also made to some portions of bony armour ob- 

 tained in the Rio Seco, in the Banda Oriental, and similar in struc- 

 ture to the specimen of the Pedernal. One of the portions was 

 the covering for the tail. It was hollow to its extremity, and pre- 

 sented in its concavity, vestiges of caudal vertebrae very distant from 

 each other. 



In conclusion, Mr. Owen observes, that having brought together 

 evidence of the remains of five specimens (found in the Rio Seco, 

 Rio Janeiro, Villanueva, Pedernal, and the Banda Oriental) of a 

 large Edentate species undoubtedly covered with armour, and more 

 or less corresponding with the characters of the Glyptodon, and 

 having established the characters of that genus on both dentary and 

 locomotive organs ; he trusts that he has at the same time vindicated 

 the opinion of Cuvier with reference to the Megathere, by proving 

 it to be, by its tcgumentary covering as well as its osseous system, 

 more nearly allied to the Ant-eaters and Sloths than to the Ar- 

 madillos. 



