1878.] ^>1< [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 caudals. But of the latter I am not at present able 

 to give any account. 



Both dorsal and cervical vertebrae possess centra of the general character 

 of those of Glepsydrops, 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 Ampliim- 

 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 Empedocles, 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 vertebrae. 

 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 Clepsydrops 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 vertebra? 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 vertebrae 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 posterior zygapophyses, which is decurved over 

 the neural canal. 



Measurements. M. 



No. 1, dorsal vertebra of smaller individual. 



Total elevation of vertebra 105 



Elevation of centrum 029 



" " zygapophyses 060 



