SCOTT : LITOPTERNA OF THE SANTA CRUZ BEDS. 



49 



The first and second upper molars have been badly broken and the prin- 

 cipal difference from those of the other species which may still be noted is 

 their relatively less transverse width. The third molar is proportionately 

 larger than in the other species and has a less reduced metacone, though the 

 external face of this cusp is very oblique ; the protocone is large and ap- 

 pears to have a convex internal face; the hypocone, though small, is 

 much more distinct than in L. proximum, being almost separated from 

 the cingulum, which passes around it. 



All of the lower teeth in front of ps^ are broken away level with the jaw ; 

 the lateral incisor, which is very large and procumbent, would seem to 

 indicate that the animal was a male. The last two premolars and the 

 molars have broad and heavy crowns, but the cusps are less massive and 

 the valleys much deeper and better defined than in L. floweri, but less so 

 than in L. proximum. On all of the lower molars the postero-internal 

 pillar is extremely large and prominent and, as in L. proximum, it is 

 largest in ma , while in L. floweri it is largest in ms : the talon of m^ is 

 smaller than in either of the species named. 



P-^, length {i. e., ant-post, diam.) . 



" width {i. e., transverse diameter) 

 P^, length 



" width 

 pi, length 



" width 



Upper molar series, length 

 Mi length 



" width 

 M^, length 



" width 

 M^, length 



" width 

 Ig-, greater diameter 



Measurements. 







.013 



I3-, lesser diameter 



.0055 



■013 



Lower premolar-molar series, length 



I .099 



.014 



" premolar series, length 



.052 



.017 



P3, length .... 



.015 



.0145 



" width . 





.010 



.018 



P^, length . 





.015 



•043 



" width . 





.0115 



.015 



Lower molar series, length 





.047 



.019 



My, length . 





.0145 



.0165 



" width . 





.012 



.020 



M2, length . 





.017 



.0165 



" width . 





.0145 



.014 



Mg, length . 





.017 



.011 



" width . 





.018 



The skull (PI. II, fig. i) has a long cranium, with full and rounded 

 brain-case ; the temporal ridges and sagittal crest are much as in Diadia- 

 p/iorus, but the crest is much thicker. Though the dorsal moiety of the 

 occiput is badly broken, it is plain that it was relatively broader than in 

 Diadiaphorus and even somewhat wider than in ProterotJierium. Appar- 

 ently, the periotic is entirely excluded from the surface of the skull by the 



