EDENTATA. 283 



overlapping. The typical and best-known species is Peltephilus strepent, 

 with skull about <H2m. in length, from the Santa Cruz Formation of 

 Patagonia. 



Propalaeohoplophorus. This is a primitive Glyptodont known by the 

 almost complete skeleton of the typical species, P. australis, also from the 

 Santa Cruz Formation. It is a small animal, with carapace about CH'> m. 

 in length. The skull differs from that of all other Glyptodonts, while 

 agreeing with the existing armadillos, in the exclusion of the maxillae from 

 the border of the terminal nostril. There are eight teeth on each side 

 above and below, and the first four are so much simpler than the others 

 that it has been suggested they may be true premolars. The vertebral 

 column is much arched, and the dorsal vertebrae are not fused together. 

 The limbs are long and slender. The humerus exhibits an entepicondylar 

 foramen ; the manus is unknown. The femur agrees with Dasypus and 

 differs from the Glyptodonts in the position of the third trochanter, which 

 arises at about the middle of the shaft, ; the tibia and fibula are not fused 

 together, and the hind foot comprises five digits, of which the first and 

 fifth are the smallest. A head-shield of bony polygonal plates is present. 

 The plates of the carapace are thin, with feeble sculpturing, and arranged 

 in distinct transverse rows ; at the end of the tail-sheath the successive 

 rows are firmly fused together. It is noteworthy that in the anterior 

 third of the carapace three rows of scutes at and near the inferior border 

 overlap like those of the movable bands of the carapace of the true 

 armadillos. 



Qlyptodon (figs. 162, 163). This is the typical genus of the family 

 Glyptodontidae, comprising large species, distributed throughout the latest 

 Tertiary formations of South America, and also found in contemporaneous 

 deposits in Texas and Mexico. The skull is very short and truncated in 

 front, with small flattened nasals, and the maxillae entering the border of 

 the terminal nostril. The nasal cavity is divided by a bony longitudinal 

 septum. The zygomatic arch js complete, with a long descending process 

 from the jugal bone ; and the orbit is not separated from the temporal 

 fossa. The brain is relatively very small, and the cerebral hemispheres 

 must have been quite smooth. The pterygoids enter the secondary palate. 

 The mandibular raini are fused together at the deep, spout-shaped, tooth- 

 less symphysis. There is a close series of eight teeth on each side above 

 and below, all more or less divided into three lobes by two deep grooves 

 on the outer and inner face ; and the arrangement of the various hard and 

 soft areas of dentine and cement gives the worn crown a sculptured 

 appearance, hence the generic name. The atlas vertebra is free, but the 

 axis is fused with the four or five succeeding cervicals. The dorsals are 

 anchylosed into a long tube, and the lumbar vertebrae are fused with the 

 sacrum. The caudal vertebrae are free. The limbs are stout, and the 

 digits of both feet extremely short, with almost hoof-shaped claws. The 

 scapula is short and broad ; there is no entepicondylar foramen in the 



