94 MEMOIRS OF THE CARNEGIE MUSEUM 
distance back of the odontoid process. Back of this ridge is a transverse excava- 
tion, 8 or 10 mm. in antero-posterior diameter, which is again succeeded by an 
elevated area along the posterior portion of the floor of the neural canal. As in 
Fic. 37. Lateral, Posterior, and Anterior Views of Axis of D. hollandi. } nat. size. 
Archxotherium, the pedicles of the neural arches are not pierced by foramina for the 
passage of the second pair of spinal nerves. These canals are more lateral and are 
bridged over superiorly by heavy arms of the transverse processes which unite with 
the sides of the pedicles. 
Third Cervical. — The third cervical vertebra differs from that in Archexotheriwm 
(87, p. 290) by having a proportionally much less developed neural spine, a sharper 
inferior keel, and the bony bridge, which bounds the vertebrarterial canal externally, 
Fria. 38. Lateral View of Third Fic. 39. Posterior and Lateral Views of Fourth Cervi- 
Cervical of D. hollandi Peterson. cal of D. hollandi Peterson. } nat. size. 
4 nat. size. 
narrower. As Professor Scott has stated (/. ¢., p. 290) in connection with his study 
of Archxotheriwm, there are no foramina for the spinal nerve through the anterior 
portion of the pedicles as in Sus. 
Fourth Cervical.—'The neural spine of this vertebra is damaged, but I infer 
that, as in the preceding vertebra, it is relatively less developed than in the Oli- 
gocene genus. The inferior lamella has a slightly different shape, being more deci- 
dedly separated from the diapophysial process and is less developed than in Archvo- 
therium (87, p- 290). In Dinohyus there are deep excavations on the inferior side 
