Chapter M

In anterior region: Diameter of centrum (fore-and-aft) ·075
Diameter of centrum (vertical) ·062
Diameter of centrum (transverse) ·142
In posterior region (Plate VI., Fig. 3).: Diameter
of last dorsal (vertical) ·087
Diameter of last dorsal (transverse) ·110
Average width throughout the series of neural canal ·097
Width of transverse process (anterior dorsal)
(Fig. 2, Plate VI.) ·075
Length of lamina from prezygs. to post-prezygs.
(Fig. 2, Plate VI.) ·12
Length of transverse process (middle dorsal).
(Fig. 3, Plate VI.) ·055
Vertical length of anterior dorsal from tip of spine
to hypapophysial keel ·183
Width between inner margins of metapophyses
(last dorsal) ·172

_Lumbar region_--Last lumbar (Plate VI., Figs. 4 and 5).

M.
Diameter of centrum (fore-and-aft) ·095
Diameter of posterior face (transverse) ·111
Diameter of posterior face (vertical) ·078
Extreme width between transverse processes ·214
Width between pre-zygapophyses ·110
Length of neural spine from lamina ·060
Vertical length from tip of spine to lower side of
centrum ·194

_Sacral region._

M.
Length of sacral series ·264
Transverse extent of sacral series ·298
Diameter of first vertebra at free end (transverse) ·109
Diameter of first vertebra at free end (vertical) ·072
Diameter of first vertebra at free end (tore and aft) ·070
Diameter of last vertebra at free end (transverse) ·053
Diameter of last vertebra at free end (vertical) ·031
Diameter of neural canal at first vertebra
(transverse) ·100
Diameter of neural canal at last vertebra (vertical) ·018
Long diameter of first transverse foramen
(internal side) ·076

_Caudal region_ (Fig. 6, Plate VI.).

M.
Length of first four ·252
Diameter of centrum, first (fore-and-aft) ·061
Diameter of neural canal of first (transverse) ·035
Extent of transverse process in first ·085
Extent of transverse process in fourth ·046
Fore-and-aft width of transverse process of first
in the middle ·048

_Ribs._--Description based upon two perfect ones, and parts of four more.

The ribs, as in _Dinoceras_, "resemble very much those of the Mastodon." The capitulum has two convex facets, separated by a narrow groove. The sternal end in one is very much expanded, but less so in the other. The tubercle is small, and is situated upon the prolongation of the lamelliform process for the intercostal muscles. The angle is much sharper than in the corresponding ribs of _Mastodon_.

_Measurements of Ribs._