ANATOMY OE BAL2ENOPTEKA EOSTEATA. 
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There were eleven dorsal vertebrae. The first closely resembled the last cervical, ex- 
cept that its centrum was thicker, and was furnished with longer and more robust and 
compressed diapophyses. 
The remainder of the dorsal vertebrae had their lateral processes more horizontally- 
placed and more elongated, those of the anterior six being directed forwards, while 
those of the eighth to the eleventh pointed backwards, and those of the seventh pro- 
jected at right angles with the axis of the body of the vertebra ; these processes were 
thickened at their free extremities, where they articulated with the ribs ; their neural 
spines were flattened and somewhat quadrilateral in outline, with their free extremities 
directed, those of the second and third upwards, and the others backwards and upwards, 
each of them becoming gradually more decumbent and elongated as they descended 
towards the lumbar region. The zygapophyses were prominent and directed forwards ; 
rudimentary parapophyses were developed in the first and second dorsals, similar to those 
described by Lilljeborg in a female skeleton preserved in the Museum at Bergen. The 
bodies became more robust as they descended towards the lumbar region, and were all 
obtusely carinated on then inferior surfaces*. 
The neural canal, which in the cervical and upper dorsal regions had its greatest 
diameter in the transverse direction, in the lower dorsal region gradually diminished 
in calibre, and its major axis changed its direction from transverse to vertical. 
The bodies of the lumbosacral and caudal vertebrae were mostly solid and massive with 
flat and thin lateral processes, which gradually became shorter and thicker as they 
approached the tail. Those of the first lumbosacral vertebrae were directed transversely 
outwards, those from the second to the twelfth were inclined forwards, those of the thir- 
teenth and fourteenth looked directly outwards, and the remainder were turned forwards ; 
at the nineteenth the lateral processes were entirely suppressed. Their neural spines 
gradually increased in length to the middle of this region, and then rather rapidly dimi- 
nished towards the tail, the seventh caudal being the last that possessed a spine. The 
centrums presented on their anterior surface a bluntish keel, which gradually increased 
in prominence to the thirteenth ; those of the twelve lower caudal were perforated on 
each side of their dorsal aspect by a canal which opened on the ventral surface in a de- 
pression situated external to the articular surfaces for the chevron bones. The crest on 
the anterior aspect of the caudal vertebras was bifid, the lateral ridges being separated 
by a central longitudinal groove, which was pierced about the central part of each 
centrum by two foramina. • 
The articular processes or zygapophyses of all the lumbo-sacral vertebrae articulated 
with each other, while those of the caudals were free. 
The foramina on the dorsal aspect of the sixteenth vertebra was situated at the root 
of the transverse process, but when these processes ceased to exist, these apertures per- 
forated the sides of the centrum on the dorsal aspect. 
* This differs from the description of Lilljeborg, who says that none of the dorsal vertebrae are ridged on 
the lover side of the corpus. 
