38. Fietp CoLumBiAN MuseEuM—GEoLoGey, VoL. II. 
few arches that were recovered complete, or nearly so, from different 
parts of the series, the restoration of the intervening parts of the 
series has presented few difficulties. 
The spines decrease very slightly in height, in breadth and in 
thickness. <Anteriorly they are directed somewhat backward, but 
soon become quite vertical in position. In the posterior cervical and 
anterior dorsal region the spines present a much larger, oval and 
truncate extremity for ligament or cartilage; this surface measures 
from twelve to fifteen millimeters in width in some of the posterior 
cervicals. In the posterior dorsals the extremity is narrow—three or 
four millimeters in width. The first diapophysis* is small, for the 
attachment of a small, short rib, and is situated low down on the 
pedicle,t+ close to the sutural surface. The next is much stouter and 
longer, for the attachment of a long and strong rib. The next two or 
three ascend progressively on the pedicle, until in the fifth the upper 
margin of the root is above the plane of the anterior zygapophyses. 
They retain this position throughout the series, the last two or three, 
only, descending toward the centrum. The diapophyses have ac- 
quired their greatest length by the sixth or seventh, and are directed 
upward and outward. In the articulated skeleton there is a deep 
costo-spinal groove on either side. The zygapophyses are largest 
and stoutest in the posterior cervical region, decreasing gradually in 
size, and becoming obsolete at the base of the tail. Throughout the 
dorsal region they are but slightly cupped, and are directed dorsad 
and ventrad, at only a slight angle from the median plane. There 
are no indications whatever in any region of a zygosphene. The 
centra throughout this region were more or less crushed in the 
specimen, but seem to be very uniform in character. Their size is 
but very little different from that of the posterior cervicals, their 
length no greater; the venous foramina on the ventral side become 
gradually more remote from each other. 
Some of the dorsal ribs were so badly decomposed that they could 
not be recovered from the matrix; others were so intermingled with 
other bones that they could not be removed entire. The larger part, 
however, have been recovered and restored nearly to their living 
condition. The anterior long ribs are flattened, with an exparided 
head, only moderately curved and with the distal extremity only a 
little attenuated, the cartilaginous continuation evidently of some 
*Baur (Anatom. Anzeigerix, No. 4, 1898, p. 120) would restrict this term to the process bearing 
the head of the rib in the Stapedifera. 
+Seeley has proposed to call these vertebre in which the rib is ascending from the centrum, 
pectorals. 
