310 



DR. C. W. ANDREWS ON A NEW SPECIES OF 



The outer face of the mandibular ramus is convex from above 

 downwards, the convexity being most marked in the symphysial 

 region, which extends back to the level of the anterior root of 

 pmg ; in Frozeuglodou it does not seem to extend beyond the 

 hinder end of pm,,. The symphysial surface itself bears a 

 strongly rugose surface for union with the opposite i-amus, the 

 rugosities being most strongly developed posteriorly : the union 

 between the two rami must have been much stronger than in 

 Zeugloclon or Prozeuglodon, where the symphysial surfaces bear 

 only a few straight and slightly developed longitudinal rugosities. 

 Behind the symphysis the inner face of the ramus is convex from 

 above downwards immediately beneath the alveolar border, but 

 towards the ventral edge becomes gently concave in the same 

 direction. The ventral border is nearly straight from before 

 backwards as far as beneath the hinder end of m^, where it turns 

 somewhat upwards for a short distance and then continues in the 

 original direction, so that at this ]3oint a slight step-like prominence 

 is formed (text-fig. 1, n). The posterior portion of the ramus is 

 lost in both specimens. In its general form the mandibular 

 ramus is very similar in form to those of Prozeuglodon and 

 Zeuglodon, but at the same time is distinguished from them by 

 being more massively constructed and by the presence of the 

 slight step in the ventral border referred to above. 



Text-figure 1. 



mj mz m.3. 



Left ramus of mandible of Pap2yocetus htgardi, gen. et sp. nov. 

 n, step-like notch on lower bonier (M 11086). About ^ nat. size. 



Teeth. — So far as can be ascertained the dental formula of the 

 mandible was I. 3, 0. 1, Pm. 4, M. 3 — the full Eutherian dentition. 

 Of these, Ij is represented in specimen B by the socket only ; 

 this is situated at the extreme anteiior end of the jaw and was 

 separated from its fellow of the opposite side by a very thin 

 wall of bone only. The tooth must have been directed forwards 

 and somewhat upwards. I^ and 1,^ are I'epresented in the same 

 •specimen by their broken bases, which are somewhat wider, from 

 before backwards than from side to side, and appear to have 

 -possessed a slight keel on the anterior border. Of the incisors 

 I.^ is much the largest, the longitudinal diameter of its base being 

 about 27 mm., while in I^ this measurement is only 13 mm.; 

 I^ was about the same size at I^. This relatively large size of 

 J seems to be characteristic of this genus, not occurrino- in 



