JiAMMALIA. 



65 



I)}' Mocrilhcrimii (I'ig. 02), wliich comprises still smaller 

 species whose relation to Eleplias would hardly be suspected 

 if all the intermediate gradations were unknown. Here the 

 cross- ridged molars are first becoming recognisable ; one pair 



Wall-case 

 43. 



Fig. 61. — Skull aud lower jaw of PaLvoviastodon bendneUi, showing 

 elongated chin with pair of terminal cutting teeth [l.i.), from the 

 Upper Eocene of the Fayum, Egypt ; one-twelfth nat. size. nar. 

 position of nostrils ; //./. upper incisor or tusk. (After C. W. Andrews.) 



Fig. 02. — Skull and lower jaw of Mocritherium lyonsi, from the Middle 

 Eocene of the Fayum, Egypt; one-seventh nat. size. ant. orb., 

 antorbital foramen ; c, canine ; c.r. oc. , exoccipital ; /r., frontal ; i. 1-3, 

 incisors; ju., jugal; m. 1-3, molars; m.v., maxilla; n., nasal; p.a., 

 parietal; prt/-. oc, paroccipital ; j).w. 2-4, premolars; }>■ mx., pre- 

 maxilla ; pt., post-tympanic process of squamosal; s.oc, supra- 

 occipital ; sr/., squamosal. (After C. W. .\ndrews.) 



<it' incisors above and below is growing at the expense of its 

 fellows to ))ecome real tusks ; and the arrangement of the 

 bones ol' the skull is beginning to sliow features which are 

 kno\\ii only in the order Proljoscidea. S(^veral instructive 

 fragments and plaster casts ol" skulls from tlie Caii'o IMuseum 

 are placed in IMercase 43. 



