ANOMODONTIA. 



151 



temporal arcade ; and the quadrate bone exhibits a tendency to 

 extreme reduction in size. The occipital condyle is distinctly 

 bilobate. The premaxillse are separate. The meeting of 

 palatal plates from the maxillae in the middle line, sometimes 

 followed behind by similarly united plates from the palatines 

 (fig. 95, s.p.), causes the actual opening of the posterior nares on 

 the roof of the mouth to be displaced backwards, as in certain 

 chelonians and in mammals. Teeth on the palate are insigni- 

 ficant and rare. The mandible bites within the upper jaw and 

 usually exhibits a persistent suture at the symphysis of its two 

 rami, but never any vacuity in the latter. The skeleton of the 

 trunk is imperfectly known ; but the humerus has an expanded 

 distal end, sometimes with an ectepicondylar as well as an 

 entepicondylar foramen ; the scapula has a large " spine," quite 

 mammalian in aspect ; and there is a small vacuity between 

 the pubis and ischium in the pelvis. 



pmoc 



art. 



FIG. 95. 



Galesaurus planiceps; palatal aspect of skull, with mandible, two-thirds 

 nat. size. Karoo Formation (Permian or Triassic) ; South Africa, art., 

 articular; b.s., basisphenoid ; d, dentary; ecpt., ectopterygoid ; pL, pala- 

 tine; pmx., premaxilla ; pt., pterygoid ; s.p., secondary palate obscuring 

 the primitive opening of the posterior nares; spl., spleuial ; r, single 

 vomer with median vertical plate in front descending to meet the secondary 

 palate. (From specimen in British Museum, no. B. 511.) 



