1878. ] 517 [Cope. 
described, belong to the cervical and dorsal regions, and it is not unlikely 
that one series which is not yet extricated from the matrix, includes also 
lumbars, sacrals and cauda!s. But of the latter I am not at present able 
to give any account. 
Both dorsal and cervical vertebrze possess centra of the general character 
of those of Clepsydrops, with small intercentra, The neural arches present 
important differences. There is on the posterior aspect,-below the zyga- 
pophyses a well developed hyposphen, and on the anterior face a corres- 
pondingly strong hypantrum. The structure is identical with that which 
I have described as present in the genera Camarasaurus and Amphice- 
lius, but is rather better developed. It disappears at some posterior point 
of the dorsal series. The zygapophyses are much elevated and spread 
apart in Hmpedocles, and are connected together back to back. From this 
junction the diapophysis depends, forming a vertical septum whose in- 
ferior extent is greatest on the cervical, and least on the dorsal vertebre. 
It is undivided, and as there is no capitular facet on the centrum, the 
rib had but a single head. The expansion of the diapophyses with that of 
the posterior zygapophyses gives to the posterior side of the vertebra a re- 
markable appearance, and forms an oblique roof above the centrum. The 
neural spine is not elevated, and is very robust, being in some cases greater 
in the transverse than the antero-posterior diameter, again approximating 
remotely Camarasaurus. Of the dentition nothing is known, but some 
jaws with teeth of animals allied to Olepsydrops may belong here. Proba- 
bly other portions of the skeleton are in my possession, but I am unable as 
yet to correlate them. 
Char. Specif. The diapophyses are not long, and their articular surfaces 
are quite elongate downwards and forwards, especially on the cervical cen- 
tra. On more posterior dorsals the diapophysis arises exclusively from the 
neural arch, but maintains its very narrow oblique articular face. On all 
the vertebre the centrum is about as long as wide, with regular marginal 
angles without bevel for intercentrum. The sides are concave, and the in- 
ferior median line horizontal, and thickened. The neural spine is short in the 
dorsals, and with a subquadrate section, with the angles lateral and antero- 
posterior. The apex is excavated at the extremity. The space between the 
planes of the opposite zygapophyses is strongly convex. The latter have 
horizontal faces. In other vertebree the neural spine is more transverse, and 
the zygapophyses are separated on the median line by a smaller fossa on 
the anterior face of the arch, and a larger one on the posterior face. 
In a specimen in which the hyposphen has disappeared, it is represented 
by a ridge connecting the pos‘erior zygapophyses, which is decurved over 
the neural canal. 
; Measurements. M. 
No. 1, dorsal vertebra of smaller individual. 
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Wilevahon! Of CeMirUMiiwy ats cele ciimeetoctssrcinciiesieciscss oOo 
wt St LY PAMOPOYNCS: cus witwieste ste aticaitee fos. 5s 2000 
