TEJiTlAIlY VERTEJ3RATA OE THE EAYDM. 
1 12 
produced backwards in tlie middle line into a blunt liypapophysis and bears on its 
up.per surface a fairly well-defined surface for the odontoid process. 
In the (ixis (PI. XI. fig. 2) the neural spine [n.si).) is high and directed backwards ; 
its sliarj) 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 
n ith 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 luemal 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 ])roduced downwards into a sort of haemapophysis. 
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 
(? 3rd or 4th, PI. XI. 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 haemal ridge which deepens 
somewhat behind. The neural spines [n.s]).) are short, pointed, and backvvardly 
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 differs 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.]).) 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 rih. The 
nenral spine is a high, pointed, and backwardly directed ])rocess. 
A nearly complete vert(‘bral column (C. lOOUo), associated with a very imperfect 
skull, was collected from the Middle Eocene beds, and has already been mentioned as 
undoubtedly belonging to a species oi lllmitJierinm, jiossibly even to a large individual 
of M. Iij 0 )isi. (’onsidering both the size and some diherences in details of structure 
in such vertebi'ie as can be compared, it seems advisable to refer to this sjiecimen 
as Mmritlicrhuti S]). until suflicient evidence is available either to justify regarding it as 
belonging to a new species or definitely rck'gating it to J/. hjond. 'I'he vertebrx* 
