EEMAINS OF FOSSIL POEPOISES KELLOGG 



21 



direction. A short neck or constriction beloAV the enamel crown 

 approyimately 1.5 mm. wide accentuates the swollen appearance of 

 the roots of these teeth. The surface of the enamel crown is nearly 

 smootli. The inner and outer margins of the crown are rounded and 

 not ttrongly carinate. As viewed from in front, the outer margins 

 of ihe crowns are convex and the inner margins are concave. The 

 apical portions of most of the teeth exhibit a tendency to incline or 

 curve backward. A rudimentary second root is present on some of 

 the teeth. 



Measurements of the teeth in the left maxilla, in millimeters. 



Height of enamel crown... 



Anteroposterior diameter of crown at base 

 Transverse diameter of crown at base 



Four- 

 teenth 



9.4 

 3.4 



4.5 



Seven- 

 teenth 



9.8 

 3.3 

 4.5 



Forty- 

 ninth 



7.3 

 2.7 

 3.9 



Fifty- 

 first 



6.6 

 2.6 

 3.9 



MaiHlWle. — As restored the symphysial portion of each mandible 

 IS slightly longer than the free portion. The rami are firmly anky- 

 losed throughout the symphysis and curve upward. This curvature 

 (pi. 2) permits the teeth in the upper and lower jaws to interlock 

 when the mouth is closed. All of the teeth are not located along the 

 symphysis (pi. 3) for at least 14 were present on the ascending por- 

 tion of the ramus. Judging from the alveoli, there w'ere originally 

 at least 50 teeth on the right ramus and 51 on the left. If the ex- 

 tremity had been preserved the figures given above would be in- 

 creased. The symphysial portion of the combined lower jaws tapers 

 anteriorly and at the same time the dorsoventral compression becomes 

 more marked. Between the tooth rows the upper surface of the 

 symphysis is relatively smooth. The depth of either mandible at the 

 proximal end of the symphysis is nearly three times that at the ex- 

 tremity. The distance (118 mm.) from the symphysis to the last 

 tooth is greater than the interval (80 mm.) between the opposite rows 

 at the level of this tooth. 



Back of the tooth row and on the internal face of the ramus there 

 is an orifice for the large dental canal. Beyond this point the 

 internal wall is incomplete and the ramus consists mainly of a thin 

 shell or bone. A thin inwardly curved plate which extends down- 

 ward from the superior margin of the coronoid portion of the 

 ramus roofs the concavity above the dental canal. The external 

 surface of the ramus in this region is convex. At a point 110 mm. 

 behind the last tooth on the right ramus and 61 mm. behind the 

 corresponding tooth on the left, the coronoid process and that portion 

 of the jaw which lies above the level of the condyle is missing. Part 

 of the coronoid process has been restored on the left ramus (pi. 3). 



