ORDER ANOMODONTIA. IO55 



size of the exoccipital elements of the occipital condyle in the 

 present order. In the presence of an entepicondylar foramen to the 

 humerus the Anomodonts agree with Rhynchocephalians, Sauro- 

 pterygians, and Mammals. In many cases (fig. 978 bis) the precora- 

 coid forms a large plate-like bone suturally united with the whole of 

 the anterior border of the coracoid, and also articulating largely with 

 the acromial process of the scapula ; thus exhibiting a parallelism 

 between the structure of the pectoral and pelvic girdles found in no 

 other reptiles. The above features, together with certain points in 

 the structure of the palate mentioned below, suggest very strongly 

 the descent of the Monotreme Mammals from the same primitive 

 stock as that which gave rise to the Anomodonts. If, moreover, Dr 

 Baur is right in considering that this order does not include the 

 direct ancestors of Mammals, it would appear that the development 

 of its more specialised representatives has followed a course in some 

 respects parallel to that of Mammals. 



Suborder i. Pariasauria. — This suborder includes the most 

 generalised members of the order, which make the nearest approach 

 to the Amphibia. The cranium is at once characterised by the 

 roofing over of its postero-lateral or quadratic region, after the Laby- 

 rinthodont manner, by the postorbital, squamosal, and opisthotic 

 bones. Typically the palate, which approximates to an Amphibian 

 type, and has been compared to that of Nyrania (fig. 825), appar- 

 ently has no flooring of the nasal passage to form secondary posterior 

 nares. The skull also has two temporal arcades, and the external 

 surface of the cranial bones is frequently sculptured, as in the typical 

 Labyrinthodonts. The vertebral centra retain a notochordal canal ; 

 the number of sacral vertebrae was limited to two, of which only 

 one supports the ilium ; and intercentra may be present. The 

 pelvis is of a Labyrinthodont type, the ilium forming a triangular 

 plate elongated in a direction oblique to the axis of the sacrum, 

 with which it articulates obliquely ; and there being no obturator 

 foramen between the pubis and ischium. The humerus probably 

 belonging to this group differs from that of other Anomodonts in 

 the slight expansion of the extremities, and in that the lower aperture 

 of the entepicondylar foramen opens on the distal surface of the bone. 



Family Pariasaurid^e. — The type genus Pariasaurus occurs in 

 the Beaufort beds of the Karoo system of South Africa, of which the 

 vertebrate fauna presents a Triassic facies. The best known species 

 (P. bombidens) attains the dimensions of a large crocodile ; and, with 

 the unfortunate exception of the limbs, the entire skeleton is known, 

 and has been described by Professor Seeley. In addition to the 

 sculpture on the bones of the skull, mucous canals, like those of the 

 Labyrinthodonts, are also present. The teeth are of uniform size, 

 and, although anchylosed to the bone, are set in distinct sockets, 



