4,2 THE STEUCTUEE AND RELATIONSHIPS OF ANCODUS. 
n . nrp verv widely separated, while the an- 
of theoppoA-* brought close together. This is 
tenor jmd postenor processes 0 „eunl ‘itches together with their short- 
i„co..se,ue,.ceof the g«.t resdth o he^^^ 
rve';”Ch«e nean, f«s. and present 
IrdLctly upw^diydownward, with hut little ^"the 3d' 
neural spines increase in height successively rom 
vertebra the spine forms a low and inconspicuous ridge, while on the 5th it has 
attained considerable heightand thickness. The transverse processes mos resemble 
those usual among the Pecora, aside from the differences caused by the smaller 
elongation of the centra. On the 6th the inferior lamella is very large and dist.nctly 
differentiated into two parts, much as it is in and the diapophysial element 
is as conspicuously developed as on the 6th. The latter has a still larger inferior 
lamella, with thick and roiighcued free m.argin and relatively short diaixiphysis. 
The last cervical is, as usual, without any pleurapophysis, and the transverse process 
is in the form of a long, stout bar, with slight upward curvature. All the cervieals, 
except the atlas and the 7tli, display the vertebrarterial canal. 
The thoracic vertebrcc must have numbered at least thirteen, since that many 
ribs of the right side are in position in one of the specimens. The nine anterior 
thoracic vertebrm have centra of almost uniform length, which (piite strongly 
resemble those of the deer. The Ist and 2d have the broadest and most distinctly 
keeled centra. The spines are compressed, slender, inclined very strongly back- 
ward and are rather short, as compared with those of Sus or of the larger Pecora. 
The transverse processes are of no great length, but they have very large facets for 
the tubercles of the ribs. 
The lumbar region must have contained at lecast six vertebrm, that many being 
preserved in the New York specimen of A. americanus, already referred to, which 
indicates that the number of trunk vertebrm cannot have been less than nineteen, 
though the number of thoracic and lumbar vertebrm was doubtless subject to specific 
variation. The first lumbar has a centrum which is long and deep, but slender, tri- 
hedral and contracted in the middle; the faces are slightly opisthocoelous. Passing 
backward, the centra become more and more broadened and depressed, a change 
which reaches its maximum in the sixth. In spite of this progressive diflerence of 
shape, the first five vertebrm have centra of almost uniform length, while the 6th 
is considerably shorter than the others. The processes are nearly all broken away, 
but enough remains to show that the neural arches are low and short antero-poste- 
riorly, and that the transverse processes are very broad and thick. 
Of tlie sacrum the first vertebra is preserved in the same skeleton, which has 
yielded the lumbars. The anterior face of the centrum is very broad and low and 
the posterior foce much narrower and lower still. The neural canal is likewise very 
ow, but wide. The pleurapophyses are very large and heavy, both vertically and 
transversely. Apparently, the pelvis was borne entirely by this vertebra and had 
