340 THE ANATOMY OF VERTEBRATED ANIMALS. 



The odontoid vertebra is ankylosed witli a greater or 

 smaller number of its successors. The cervical vertebrae 

 which follow these have peculiar accessory articular sur- 

 faces ; and the hinder dorsal and the lumbar vertebrae are 

 also provided with accessory articular facets and processes. 

 A number of the anterior caudal vertebrae are always 

 ankylosed with one another, and with the true sacrals, to 

 form the long sacrum ; and the transverse processes of 

 some of these caudal vertebrae ahxit against the inner sur- 

 faces of the ischia, and become ankylosed therewith. 



The first rib is broad and flattened, and the anterior piece 

 of the sternum is expanded. The succeeding vertebral ribs 

 are connected by ossified sternal nbs with the stemiun, 

 and these are articulated, not only with the sternum, but 

 with one another. 



In the carpus, the cuneiform bone bends round the unci- 

 form, and articulates with the fifth metacarpal, when that 

 bone is present. The ungual phalanges of the manus are 

 long and pointed. The femur has a third trochanter, and 

 the four inner metatarsals are much longer than they are 

 broad. 



The division of the Glyptodontidce contains the single 

 genus Glyptoclon, which is essentially a large armadillo; 

 but it departs, in some respects, not only from all these 

 animals, but from all other Mammalia, and even stands 

 alone among the Vertebrata. 



The carapace covers the whole body, but presents no 

 movable thoraco-abdominal zones, inasmuch as it consists 

 of polygonal plates fii-mly united together, and fringed by 

 a margin of scutes with raised conical surfaces. 



The nasal bones are short and broad, and their free 

 ends do not project so far as the premaxillae ; whence the 

 anterior nasal aperture looks slightly upwards as well as 

 forwards. The premaxillae, however, are very small bones, 

 and if they unite with the nasals at all, do so for a very 

 short distance. The anterior portion of the jugal arch 

 gives off a great downward process. The mandibular sym- 

 physis is very long, and the posterior alveoli of the man- 



