8 



TEETIAET VEETEBEATA OE THE FAYtTM. 



situated between the upper edges of the facial processes of the premaxillae: this 

 will be described more fully in the account of the latter bones. The anterior 

 face of the prenasal bar is flattened and towards its lower end deeply pitted by 

 what seem to be muscle-impressions : possibly the animal possessed a pointed mobile 

 upper lip, something like that of Rhinoceros hicornis, and the muscles inserted in 

 these impressions were concerned in its movements. The general form and relations 

 of the prenasal bar are well shown in PL I. and PI. IT. fig. 1a; also in text-fig. 2. 



Text-fig. 2. 



Skull of Arsini.iiherium zitieli: oblique view of anterior portion showing the relation 



of the nasal and maxilla in the narial opening. 



«.o./., antorbital foramen; i. 1, i. 3, incisors; jw., jugal; Z., lachrymal; mes., prenasal bar; me^.r/., mesethmoid 



groove ; mx., maxilla ; na., nasals ; nar., nares ; pm. 2, pm. 3, premolars ; pmx., premaxillae. 1 nat. size. 



The horns themselves are borne on a common base, formed by the frontals 

 posteriorly, but for the rest by the nasals alone. The mid-dorsal line of the 

 basal portion is marked by a shallow groove, but in the adult the median suture 

 is completely obliterated. A section of the basal region taken at right angles to 

 its dorsal surface would give an arc of about three quarters of a circle, though 

 somewhat inflated at the sides. From this base the paired horns arise and project 

 forwards, upwards, and somewhat outwards. In adult, probably male, animals they 



