EOTHEEIUM ^GYPTIACUM. 207 



forms the posterior border of the large anterior palatine foramen (a.p.f.). Behind 

 this the palate is deeply concave from side to side, but on either side is raised into a 

 prominent ridge lying just within the alveolar border and extending back to the level of 

 the alveolus of the tooth here regarded as pm. 2. Behind this, the palate widens out, its 

 greatest width being about opposite the front of m. 2. The transverse suture with the 

 palatines is about opposite the front of m. 1 ; the posterior palatine foramina are either 

 very small or absent. On the outer side of the maxilla the broad zygomatic process 

 rises by a very long base, and its ventral surface is very little above the alveolar border ; 

 the antorbital foramen (a.o.f.) is smaller than in JEosiren. The suture between the 

 jugal (ju.) and maxilla is not very distinct, at least posteriorly ; probably the relations 

 of the two elements were almost as in Manatus ; at any rate, it is clear that the jugal 

 made a broad squamous overlap on the upper surface of the zygomatic process of the 

 maxilla, so that it forms the actual floor of the orbit. Behind this, it widens out 

 suddenly, being produced downwards into a blunt point and upwards into a slight 

 postorbital process. Posteriorly it becomes a mere rounded rod of bone underlying 

 the zygomatic process of the squamosal. 



The palatines {pi.) form the greater part of the palate as far as the front of the 

 molar series. The posterior border of the palate seems to have been a little behind 

 the last molar, but in this specimen it is somewhat incomplete. The descending plates 

 bounding the mesopterygoid fossa no doubt are formed by the palatines in front and 

 the pterygoids behind, but the sutures are indistinct; the same is the case with the 

 junction of the lower part of the alisphenoid with the pterygoid. The body of the 

 alisphenoid (al.) joins the parietals above, the squamosals.behind, and the I'rontals in 

 front ; its lower border forms the outer lip of a deep groove, at the bottom of which 

 the optic and other foramina opened ; this groove is continued forwards to the orbit 

 by the lower edge of the frontal. The orUtosphenoid is not distinct. The tympanic 

 [ty.) is incomplete on both sides. 



The dentition in this specimen is of great interest. The dental formula seems to 

 have been : i. 3, c. 1, pm. 4, m. o. The anterior incisors are very remarkable teeth, and 

 as in the later forms they are situated at the end of the snout, while they are already 

 somewhat enlarged. They have very long roots, and their enamel-covered crowns are 

 a little compressed from side to side; the anterior border is rounded, the posterior 

 sharp. The outer face is flat or slightly convex, while the inner is raised into vertical 

 ridges, so that the worn surface of the tooth has the appearance shown in text-fig. 66, B, 

 looking almost as if it were a complex tooth composed of several elements. The thick 

 enamel has a peculiar appearance, owing to the development of numerous obscure 

 wrinkles. Behind these teeth there is a diastema of considerable length separating 

 them from the second incisors, which were large teeth situated on the edge of the 

 premaxilla and not displaced outwards as in Eosiren. Immediately behind these were 

 the third incisors, the posterior borders of the alveoli of which are in contact with the 



