NO. 7 EARLY CENOZOIC VERTEBRATES — FRIES ET AL. 1 3 



and jugals. Within the orbit they have no greater development and 

 are excluded from articulation with the palatine bones by an inter- 

 posed contact between the prefrontal and jugal. The vertically elon- 

 gated lachrymal foramen notches the inner edge of the lachrymal bone 

 and is bounded mesially by the prefrontal. 



A distinct post frontal is present on each side and is a small elongate 

 bone situated at the posterodorsal border of the orbit, articulating 

 with the frontal and postorbital. The latter element is large and tri- 

 angular with a high, short apex in contact with the frontal and parie- 

 tal dorsally and with its long expanded base extensively articulating 

 with both the jugal and squamosal ventrally. 



The jugals are low curved bones forming the lower border of the 

 orbits. Anteriorly each joins the lachrymal. Posteriorly the bones 

 meet the postorbitals in oblique sutures, which are highest at the 

 orbital margin. It may be assumed also that they are in contact with 

 the anterior extremities of the squamosal posteriorly. A blunt process 

 projects from the ventral margin of the jugal, which is not produced 

 backward as a spur but merely descends to a union with the ectoptery- 

 goid behind the posterolateral extremity of the maxillary. 



As a result of the incompleteness of the parietoquadrate arch no 

 evidences of the tabular elements are preserved. The osseous tissue 

 of the squamosals has likewise been destroyed by weathering. How- 

 ever, the outline of a portion of the left squamosal is impressed in the 

 matrix and indicates the completeness of the supratemporal arcade. 

 The quadrate possesses a narrov/ internal flange and a wide external 

 one. Both portions are deeply concave posteriorly and the lateral one 

 is much wider at the top than at the bottom. 



Tips of the median dorsal spine and the left posterolateral process 

 are the only remnants of the premaxillary bone preserved. The 

 maxillary is of the customary triangular shape with posteriorly pro- 

 duced alveolar base and high anterodorsal lamina abutting on the 

 nasal and prefrontal. 



The right and left halves of the palate are nearly complete. The 

 pterygoids articulate with the dilated and dorsoventrally compressed 

 basipterygoid processes by an elongate facet. Behind this point, the 

 bone thins, becomes vertically inclined, and extends outward and 

 backward to the quadrate region. Anteriorly it is directed parallel to 

 the medial line and arches upwardly to a sutural connection with the 

 palatine. A few relatively large teeth are set in a single rov/ near 

 the inner edge of this forward segment of each pterygoid. Slightly 



