348 Wort?7ia7i — Studies of Eocene Mammalia in the 



105 



The superior incisors, figure 105, more nearly resemble the 

 upper canines of Hajpalemur griseus than any other teeth 

 with which I have been able to compare 

 them. They are, however, less pointed, 

 somewhat thicker in front, and have a 

 decided twist. The office of this torsion 

 was doubtless to brin^^ into apposition flat- 

 wise the points of the two teeth implanted 

 by diverging roots. Both the crowns and 

 the roots are considerably compressed 

 from side to side, the crown terminating 

 behind in a sharp cutting edge. In cross 

 section, therefore, the tooth gives an ellip- 

 tical outline, pointed behind. There is a 

 worn surface upon the front face of the 

 crown, showing the point where it most 

 frequently impinged upon the lower inci- 

 sor. The crown is completely invested 

 with enamel, and the tooth was implanted 

 by a distinct root and was therefore of 

 limited growth. The remaining cranial fragments furnish 

 little information of the general skull structure further than 

 that there w^as a well-ossified tympanic bulla more or less filled 

 w^ith cancellous tissue. 



107 



Figure 105. — Supe- 

 rior incisor of Meta- 

 cheiromys Marshi Wort- 

 man ; side view ; natural 

 size. (Type.) 



Figure 106. — Lower jaw of Metacheiromys Marshi Wortman ; side view. 

 (Type.) 



Figure 107. — The same jaw ; viewed from above. 



Both figures are one and one-half times natural size. 



Although not complete, the lower jaw, figures 106 and 107, 

 exhibits some remarkable characters. Posteriorly the lower 

 edge is broken away, as well as the coronoid, condyloid, and 

 angular regions. The front third, however, is entire, and in 

 this part the ramus displays an unusual lack of depth, but is of 

 normal transverse thickness. This latter dimension is consider- 



