278 
MEMOIRS OF THE CARNEGIE MUSEUM. 
as shown by No. 1716, at the middle of the lower part of the centrum throws 
backward a process, which fuses on the median line with a similar but more massive 
Fic. 47. Second dorsal 
of M. elatus (No. 1604). 
xX. 
process thrown forward by the posterior epiphysis. These 
projections unite to clasp the body of the centrum below 
and create on the median line a short keel-like projection 
or prominence. (Fig. 46.) The pedicels rest mainly on the 
anterior half of the centrum and show before and behind 
well-marked grooves at the point of exit of the nerve. The 
anterior facets for the head of the rib are concave, suboval 
in some specimens, in others more nearly round in outline. 
In advance of these facets on either side of the anterior 
epiphysis near its upper margin’is a small nutrient fora- 
men. The posterior articular facets for the head of the rib 
are concave and subtriangular in outline, with the angles 
rounded, having the longest side next to the posterior 
articulating surface of the centrum which receives the fol- 
lowing rib. They are located at the point of union of the 
transverse process with the body of the centrum and fuse 
with the outer margins of the posterior epiphysis, as is 
beautifully shown by specimen No. 1716. The accompany- 
ing cuts (Figs. 45 and 46) illustrate the facts better than can 
be done by a description. The articular surface for the 
tubercle of the rib looks downward and forward. The 
orifice of the neural canal shows some variation in outline 
in the different specimens. In the smaller and less mature 
specimens the opening is nearly circular. In No. 1713, and noticeably in No. 1604, 
it is transversely oval. 
Greatest height from base of 
MEASUREMENTS” OF SEcoND DorRsAL VERTEBRA. 
1604, 1703B, 1712, 1713, 1714, 1716, 1717, 
mm. mm. mm. mm. mm, mm. mm. 
centrum to top of 
suakeh hs Meievaoanee toate 314 230 307 275 204 248 183 
Greatest transverse diameter, measured across 
LLANSVerseypPTOGESSCSenieeee eisai 172 140 155 156 120 141 104 
Greatest antero-posterior diameter, measured 
from front of prezygapophyses to back of 
postzycapophiysess erence 
90 64 72 76 60 65 51 
Length of centrum along floor of neural canal.. 50 40 48 42 84 42 28 
24 Numbers in italics show that the measurement is approximate only, the specimen being broken. 
