PLIOSAUKTJS. 5 



columella cranii or epipterygoid (col.). This bone is stout and seems to have been oval 

 in section, narrowing rapidly towards its summit, where it no doubt joined the lower 

 edge of the parietal, though the crushing to which the skull has been subjected 

 has caused much dislocation in this region. 



The palatines (pal.) are large elongated bones ; their inner borders unite in suture 

 with the pterygoids ; anteiiorly they narrow considerably and they seem to join the 

 vomers for a short distance and perhaps take a small share in the formation of the 

 hinder border of the internal nares. Externally these bones unite in front for about 

 half their length with the maxillse, but behind this they are separated from those 

 bones by a narrow elongated suborbital vacnity [s.o.v.) which is closed behind by the 

 transpalatine. Each palatine is perforated by a foramen (pal.f.), about 1 cm. in diameter, 

 situated on the left side about 4 cm. from the hinder border of the bone and 1 cm. 

 from its inner edge ; on the right side the part of the bone lying behind and internal 

 to the opening is broken away, but it seems that the opening was a little further back 

 than on the opposite side. 



The vomers (v.) (prevomers of Broom) are large bones about 40 cm. long and for the 

 anterior four-fifths of their length anchylosed together. Anteriorly they run forwards 

 some distance between the premaxillae, behind which they are in contact with the 

 maxilla;, thus excluding the premaxillae from any share in the enclosure of the 

 internal nares. On their palatal surface the vomers are overlapped to a considerable 

 extent by the palatal plates of the maxillse and premaxillse ; between the second 

 maxillary teeth the width of their exposed surface is reduced by this overlap to a 

 narrow strip less than a centimetre wide. Between the internal narial openings the 

 united vomers form a bar, convex from side to side ; at about the middle of these 

 openings the width of the bar is about 3 cm., but at the posterior end it widens to 

 about 4-8 cm. Behind the narial openings the bones widen into a fan-shape and 

 unite with the pterygoids in the middle line by an irregular suture ; external to this 

 they have a short union with the palatines, and external to this again they join the 

 maxilla?. In no specimen, however, are the relationships of the bones in this region 

 very clearly shown. 



The premaxillae (pmoc.) consist of the massive dentigerous portion forming the 

 anterior part of the snout, and the long slender facial processes which run back on the 

 dorsal surface of the skull to a point some distance behind the external nares, where 

 they unite in suture with the anterior ends of the frontals or perhaps the parietals 

 (see below). The premaxillae bear five teeth each ; of these the first pair are small, 

 directed forwards and nearly in contact with one another on the middle line. The 

 second, third, and fourth increase in size, the two last being very large ; the fifth is 

 again small. Between the last premaxillary tooth and the first on the maxUla is a 

 diastema about 6 cm. long, crossed at about the middle by the premaxillo-maxillary 

 suture. On the palate this suture runs inwards and a little backwards to the vomer, 



