112 TEETIAET VEETBBRATA OE THE EATtJM. 



produced backwards in the middle line into a blunt hypapophysis and bears on its 

 upper surface a fairly well-defined surface for the odontoid process. 



In the axis (PI. XI. fig. 2) the neural spine (n.sp.) is high and directed backwards ; 

 its sharp anterior border is convex and the thickened posterior border bears a deep 

 fossa for the attachment of ligaments. The neural canal is high and its floor broad 

 with a median elevation, which is continuous anteriorly with the upper surface of the 

 odontoid. This process (o.d.) is relatively large, somewhat laterally compressed, and 

 bears on its ventral surface a well-defined surface for articulation with the atlas. From 

 the hinder border of the odontoid a haemal ridge runs back along the centrum and deepens 

 and widens considerably posteriorly, so that the hinder articular surface of the centrum 

 is much deeper than broad and is produced downwards into a sort of hsemapophysis. 

 The slightly convex surfaces for articulation with the atlas project laterally beyond 

 the rest of the centrum to a considerable extent. Near the posterior border of the 

 centrum there is a small transverse process perforated by the vertebrarterial canal ; 

 the small upper pedicle rises from the base of the neural arch, the larger ventral one 

 from the centrum. The posterior zygapophyses (p.z.) are oval in outline. 



The rest of the cervical series is not completely known. In the middle cervicals 

 C? 3rd or 4th, PI. XL fig. 3) the centrum is relatively short; its articular ends are 

 slightly concave in the middle, with a broad thickened border; and the concavity 

 is greatest on the posterior surface. There is a slight hsemal ridge which deepens 

 somewhat behind. The neural spines (n.sp.) are short, pointed, and backwardly 

 directed processes. The large transverse processes are perforated at their base by a 

 canal (v.c.) and are bifid at their extremities, the upper process being very small 

 and directed upwards, the lower forming a large downwardly directed flange. The 

 zygapophyses are very large. The posterior cervical diff"ers from that just noticed 

 in the fact that the spine is higher, while the downwardly directed flange is greatly 

 enlarged and has a thickened ventral border. In the anterior dorsals (PI: XI. fig. 4) 

 the centrum is short, the anterior articular surface is oval and concave in the middle, 

 while the posterior surface is also oval and slightly concave ; externally it passes into 

 a pair of facets (c.f.) for the heads of the ribs. There is a haemal ridge. The 

 transverse processes (t-jp.) are short and stout : on their outer ends there is a deeply 

 concave facet (t.f.) looking outwards and downwards for the tubercle of the rib. The 

 neural spine is a high, pointed, and backwardly directed process. 



A nearly complete vertebral column (C. 10005), associated with a very imperfect 

 skull, was collected from the Middle Eocene beds, and has already been mentioned as 

 undoubtedly belonging to a species of Moeritherium, possibly even to a large individual 

 of M. lyonsi. Considering both the size and some differences in details of structure 

 in such vertebrae as can be compared, it seems advisable to refer to this specimen 

 as Moeritherium sp. until sufficient evidence is available either to justify regarding it as 

 belonging to a new species or definitely relegating it to M. lyonsi-. The vertebra 



