14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I23 



in advance of the neurocranial processes, the elements give off antero- 

 lateral maxillary processes to which the incompletely exposed ecto- 

 pterygoid is joined. Long narrow palatine bones present flattened sur- 

 faces in ventral view. The posterior ends of the elements are widely 

 separated and continue the anterodorsal arching initiated by the 

 anterior arms of the pterygoids. Anteriorly the bones become closely 

 apposed in the median line and are decurved to a horizontal position. 

 The maxillary processes of the palatines are short and project almost 

 straight forward from the lateral borders of the bones. The vomers 

 are indicated to be short without posterior extensions and to be 

 narrowly separated by a median longitudinal fossa. 



The mandibles are robust structures. From the symphysis, each 

 diverges gradually in a sigmoidal curvature to a maximum separation 

 immediately in front of the quadrate articulation. Most details of the 

 lingual side of the lower jaws remain obscure although it has been 

 ascertained that the splenial bone on either side is a long, low element, 

 extending from the coronoid level to the region of the symphysis, 

 completely covering the Meckelian groove. In external view the 

 coronoid supports a short, high dorsal process, and its ventral margin 

 is produced a moderate distance both anteriorly and posteriorly. The 

 dentary does not extend to the posterior limit of the coronoid bone. 

 Surangular and articular bones are distinct. The posterior angle of 

 the latter is prominent, dorsoventrally flattened, and has a small 

 mesially directed retroarticular process. 



In the absence of premaxillaries and the symphyseal portions of 

 the mandibles, no complete dental formulae can be offered. The more 

 complete left maxillary and dentary contain about i6 teeth and alveoli 

 each. The teeth are pleurodont. All are closely set. As preserved, 

 the front and hind teeth appear to be somewhat smaller than the more 

 centrally situated ones of the series. Also, the lower teeth are in 

 some slight degree more robust than the upper. In labial view the 

 crowns appear low. From within, the shafts are of moderate length 

 and hollow at the base. Through anteroposterior compression, the 

 transverse diameter of the teeth is greater than the longitudinal 

 dimension. Apically the crowns are a little dilated also in antero- 

 posterior direction and pinched to a cutting edge that is alined along 

 the longitudinal axis of the jaw above the labial side of the crown. 

 These cutting edges show fine vertical wrinkles in the enamel but are 

 noncuspidate. 



