400 AXOMODONTIA. 



Pareiasaurus Owen (Fig. 221), heavy, massive creatures to 8 feet long, 

 with stout limbs, short tail ; bones of skull roughly sculptured ; bones of the 

 palate not suturally separated, with rows of small teeth, with inter- 

 pterygoid vacuity ; occipital condyle single ; the mandibular elements 

 are not separated by sutures ; 18 presacral vertebrae, 4 sacral not fused, 

 about 30 caudal with chevrons, all except the posterior caudal with 

 single-headed ribs attached to facets on the vertebrae ; wedge-shaped 

 hypocentra between the dorsal vertebrae ; the scapula slopes backwards 

 and possesses a longitudinal spine ; acetabulum closed ; limbs plantigrade 

 with 5 digits with claws, hind limbs larger than front ; sternum and 

 abdominal ribs unknown ; Karoo sandstone, S. Africa. Elginia Newton, 

 known only by the skull with spikes and horn-like projections, triassic 

 sandstones of Elgin. Procolophon Owen, a small animal the skull of 

 which shows the sutures ; there is a small lateral temporal fossa and small 

 teeth on the pterygoid and vomer ; Karoo sandstone, S. Africa. Aristo- 

 desmus Seeley, L. Trias, Switzerland. Otocoelus Cope, with a dorsal 

 carapace of 12 or more transversely extended bars of bone, Permian 

 Texas ; and other genera. 



Fia. 221. Skeleton of Pareiasaurus (Pareiasaurus) baini Seeley. Karoo Sandstone, Cape 

 Colony (after Seeley from Woodward). 



Order 2. THERIODONTIA. 



There is a single broad temporal arcade with a large superior and some- 

 times a small lateral temporal fossa ; the quadrate is small, the occipital 

 condyle bilobed ; palatal plates are developed by the maxillae and some- 

 times by the palatines ; the marginal teeth of the jaws are differentiated 

 into incisors, canines and molars ; teeth are almost always limited to the 

 dentaries, maxillaries and premaxillaries ; the external bones of the skull 

 are not sculptured ; the scapula has a mammal-like spine, but the skeleton 

 of the trunk and the appendages is imperfectly known : all from the Karoo 

 sandstone of S. Africa, but there are remains from the Permian of the 

 U.S.A. and of Russia, which may belong here. 



Galesaurus Owen, known only by the skull, dentition i - c -^ and an 



undetermined number of molars laterally compressed and in part 

 tricuspidate. Lycosaurus Owen, skull only known ; Aelurosaurus Owen, 

 known only by skull ; Cynognathus Seeley, vertebral column and limb 

 arches found with skull ; skull (Fig. 222) very mammalian ; vertebrae 



amphicoelous ; dentition i c m , molars triconodont. 



o i y 



