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Annals of the South African Museum. 



nasal, while each premaxillary forms half of the slender inter-nasal 

 process. 



The maxillary is a large bone which forms about three-fourths of 

 the lateral wall of the preorbital portion of the skull. In front, the 

 maxillary overlaps the premaxillary to such an extent that the suture 

 appears near the front of the fourth incisor. Posteriorly the maxillary 

 articulates with the prefrontal, lachrymal, and jugal. There is no 

 trace of a secondary palate, the palatine bone forming a suture with 

 the maxillary along a line a little to the inside of the molar teeth. 



Each frontal bone is about four times as long as broad. It is 

 difficult to be quite certain how much of the supraorbital border is 

 formed by the frontal, but apparently only a comparatively small 

 part. Posteriorly the frontal articulates with the post- frontal and 

 to a very small extent with the parietal. 



The prefrontal is of moderate size. It forms a long suture with 

 the anterior part of the frontal, and also articulates with the nasal, 

 the maxillary, and the lachrymal. 



The lachrymal is an irregular four-sided bone about two-thirds the 

 size of the prefrontal. It articulates with the prefrontal, the maxil- 

 lary, and the jugal. The lachrymal canal does not appear outside 

 the orbit. 



Only a small portion of the parietals is present, but it is manifest 

 that the parietal region is considerably wider proportionally than in 

 either Lycosuchus (1) or Ictidosuchus (2), and that the parietal 

 foramen must be somewhat further back than in Lycosuchus. 



Distinct post-frontal and post-orbital bones are present. The 

 former is somewhat triangular in shape and forms a considerable 

 portion of the upper and posterior margin of the orbit. Posteriorly 

 it meets the parietal, and separates the frontal from the post-orbital. 

 The post-orbital is a small bone lying behind the post-frontal, forming 

 part of the post-orbital arch and the anterior border of the temporal 

 fossa. 



The palate is fairly well preserved and is quite unlike that of the 

 higher Theriodonts, such as Galesaurus or Cynognathus. In the 

 typical Theriodonts the palate is essentially mammalian in structure. 

 A well-developed secondary palate is formed by the maxillary and 

 palatine bones carrying the internal nares back beyond the region of 

 the teeth, while a median vomer divides the nares. Between the 

 naso-palatine canals in front lie (Gomphognathus) a pair of bones 

 which I believe represent the dumbbell-shaped bone of Ornitho- 

 rhynchus and the paired so-called " vomers "of reptiles generally, 

 and which I have named "prevomers" (3). In Scylacosaurus, on the 



