HOLLAND AND PETERSON: OSTEOLOGY OF THE CHALICOTHEROIDEA. Dyk 
which looks more nearly upward and not backward to the same degree as in most 
mammals. An approximation to this feature is to be found in the cervicals of the 
horse and the tapir, but, so far as our observations extend, is not to be observed in 
so great a degree in any other of therecentmammals. The spine of the axisis very 
massive. The spines of the third, fourth, and fifth cervicals are also massive, 
low, but gradually increasing in height, that of the sixth cervical being a little 
higher than that of the fifth, while the spine of the seventh suddenly increases in 
height, and is sharply attenuated at its extremity. 
The spines of the anterior dorsals rapidly increase in height to the fourth, and 
then as rapidly decline in height until the eighth is reached. The spines of the 
dorsals from the ninth to the fifteenth are uniform in height. All of the spines 
of the dorsals rake backward, more so in M. petersoni than in M. elatus. The 
spines of the lumbars slowly increase in height from the first to the fourth and 
then grow shorter as the sacral series is approached. The spines of the sacrals 
rapidly diminish in height backward. The spines of the lumbars are nearly 
perpendicular, those of the sacral series have a backward rake. 
The transverse processes of the first dorsal are massive and tubercular. A 
rapid diminution in the size of the latter processes takes place in the second and 
third dorsals, after which the transverse processes of the succeeding vertebre 
maintain nearly the same size, gradually showing a tendency to divide into two 
tubercles, which division finally becomes pronounced in the last three dorsals, 
and reaches its highest development in the lumbars, in which the transverse proc- 
esses become broad, long, and attenuated horizontal projections steadily increasing 
in length to the sacrum. The upper process, or metapophysis, in the lumbars bears 
the prezygapophysial face for articulation with the preceding vertebra. 
A single caudal, which cannot be referred to the genera Diceratherium, Dino- 
hyus, Stenomylus, the carnivora, or other animals, remains of which were found 
in the same quarry with the remains of Moropus, has been provisionally accepted 
as representing the type of the anterior caudal vertebrae in Moropus. 
The Cervical Vertebre. 
The cervical vertebre of M. elatus (No. 1604), seven in number, were all 
recovered near to each other, and fit so exactly, being in no wise crushed or dis- 
torted, as to make it quite an easy task to assemble them. They plainly belonged 
to the same individual. 
Cervical vertebre belonging to other individuals were also recovered, though 
not always in as perfect condition, or in as complete a series, as those just men- 
