148 REPTILIA. 



known. The pelvic bones are fused together in the adult, and the 

 acetabulum is closed. There is no vacuity between the pubis and ischium, 

 but the usual small foramen pierces the pubic region. An epigastroid 

 ossification seems to occur between the pubes. The hind limb is slightly 

 shorter than the fore limb, and its digits are rather smaller. The femur 

 is imperfectly known, but exhibits a curious small intercondylar foramen 

 at its distal end. The tibia and fibula appear to articulate with one large 

 proximal tarsal bone, and there seem to have been five digits in the hind 

 foot. All ungual phalanges hitherto discovered are pointed claws. Small 

 dermal scutes seem to have been arranged in sparse series on the back. 

 All the known species of Pariasaurus were obtained from the Karoo 

 Formation (Permian or Trias) of South Africa, the typical species being 

 P. serridens, known only by the head. P. bombidens and P. baini (fig. 92) 

 are represented by comparatively complete skeletons. 



Elginia, from the supposed Triassic sandstones of Elgin, 

 seems to be related to Pariasaurus, but is known only by the 

 skull, which is about 0'15 m. in length. It is chiefly remark- 

 able for the pairs of bosses and horn-shaped defences affixed 

 to the cranial roof. 



Procolophon (fig. 94). This is a small animal, apparently not attaining 

 a greater length than 0'3 m., but very similar to Pariasaurus in general 

 proportions. The skull (fig. 94) is short and triangular in shape, exhibiting 

 the sutures between most of the bones and not externally sculptured. It 

 is remarkable for the relatively enormous size of the orbits (orb.) and 

 pineal foramen (pin.) ; also for the slight perforation of the temporal 

 arcade by an oblong foramen which evidently represents the beginning of 

 a lateral temporal vacuity (l.t.f.) The narial opening (nar.) is terminal 

 and paired. The parietal bones (pa.) are relatively large, and the identifi- 

 cation of the element (sq.) at the postero-lateral angle of the cranium is 

 a little uncertain. Outside the latter there is a deep notch or excavation, 

 evidently for the passage of the external auditory meatus; which, how- 

 ever, does not affect the quadrate. On the palate the pterygoids (pt.) 

 distinctly extend forwards to reach the vomers (v), but they do not meet 

 an the middle line so far back as in Pariasaurus. The palatines (pi.) ' 

 bound the posterior nares behind. The teeth are simple cones, those on 

 the margin of the jaws sometimes broader than long, and arranged in 

 a close, regular series of moderate size ; comparatively minute teeth occur 

 in a single longitudinal series on each pterygoid (pt.), and in at least one 

 longitudinal series on each vomer (v). The mandible bites within the 

 upper jaw. The T-shaped interclavicle (i.cl.) has a very long median arm, 

 extending beyond the ossified coracoid region, which comprises two ele- 

 ments on each side as usual (co., ep. co.). Procolophon has hitherto been 



