14 



PERMO-CARBONIFEROUS VERTEBRATES FROM NEW MEXICO. 



fuse with the quadrate and thus completely close the ear notch. A thin plate of 

 bone extends forward from the lower anterior inner edge of the tabulare and leaves 

 but a small slit-like opening at the bottom of the large depression back of the ear 

 notch. No such process is present in Chenoprosopus milleri, however, and the 

 opening, if an opening, must have been considerably larger in the latter genus. 



Little can be said of the palate; the anterior part is still inclosed in an extremely 

 hard matrix, and although the left posterior part is exposed, the bones are some- 

 what crushed and their relations can not be told with any degree of certainty. The 



Fig. 5. — Chenoprosopus milleri, X yi. Palate view. 



palate is essentially fiat. The conjoined palatines and pterygoids are broad and 

 leave a long, comparatively narrow inter-pterygoid opening. This is especially 

 true in the posterior fourth of the palate, where the posterior processes of the 

 pterygoids converge in a gentle curve inward to join the quadrate. In fact, unless 

 the skull is compressed much more than the specimen would suggest, the opening 



at this point is a mere slit. The posterior 

 pterygoid process extends upward in a thin 

 plate, inclosing a large infra-temporal vacuity. 

 This is approximately rectangular, about 65 

 mm. long and 35 mm. wide. The inner ante- 

 rior border is broken, but suggests a postero- 

 lateral process such as is seen in Cacops. 

 While the parasphenoid is not preserved, one 

 can say with some degfee of certainty that its 

 lateral extent was slight, because of the nar- 

 row inter-pterygoid space. 



Although the entire palate dentition can 

 not be shown, some of the details are worth 

 considering. Extending forward for a distance 

 of about 40 mm. from the anterior border of 

 the infra-temporal vacuity is a low rounded 

 ridge, the posterior end of which is continuous 

 with the inner border of the posterior process 

 of the pterygoid. The anterior end curves outward slightly, away from the palate 

 opening. This ridge is about 5 mm. wide and 3 mm. high and is closely studded 

 with very fine tubercles. A similar ridge, but less pronounced, runs parallel to 

 this on the outer side, at a distance of about 6 mm. It extends forward from the 

 anterior border of the post-temporal vacuity for a distance of about 25 mm. This 

 is also studded with the fine tubercles, as is the inner edge of the pterygoid to some 

 extent. Along the lateral edge of the palate, running in a line parallel to the maxil- 

 lary teeth at a distance of about 11 mm., are exposed four large teeth. These are 

 spaced irregularly, the first about 60 mm. back from the tip of the rostriun and the 



Fig. 6.^Diadectid vertebra, X >^. A, lateral 

 view; B, anterior view. 



