8 
TERTIAliY VERTEBRATA OF THE FAYOM. 
situated between tlio u|)])er edges of the facial processes of the premaxillae: this 
will be described more fidly in the account of the latter bones. The anterior 
face of the ])renasal bar is flattened and towards its lower end deeply pitted by 
what seem to be muscle-impressions : possibly the animal possessed a pointed mobile 
u])])er lip, something- like that of Blunoceros hicornis, and the muscles inserted in 
these impressions were concerned in its movements. The general form and relations 
of the ])renasal bar arc well shown in PI. I. and PI. II. fig. I a ; also in text-fig. 2. 
Text-fig. 2. 
Skull of’ Ars intrltJieritm ziiieli: oblique view of anterior portion showing the relation 
of Ihe nasal and maxilla in the uarial opening. 
u.o.T, antorbital foramen; i. 1, ?. 3, incisors ; jugal; lachrymal ; jars., ])renasal bar; jnrs.p., mesetbmoid 
groove ; Jn.r., maxilla ; nn., nasals ; nar., nares ; 2, pm. 3, premolars ; pmx., premaxilhe. j nat. size. 
'fhe horns themselves are borne on a common base, formed by the frontals 
posteriorly, bnt 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 jn’oject 
forwards, upwards, and somewhat outwards. In adult, probably male, animals they 
