01 apteryx australis - University of Texas Libraries

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The inverted bony arch for the protection of the carotid arteries is first seen to be developed
from the inner side of the inferior transverse processes of the twelfth cervical
vertebra, but the two sides of the arch are not anchylosed together ;the interspace progressively
increases inthe eleventh, tenth, and ninth vertebræ, and the groove widens and
islost at the fifthvertebra. The spinous process is thick and strong inthe vertebra dentata,
but progressively diminishes to the seventh cervical vertebra, where itis reduced to a mere
tubercle ;from the eleventh itprogressively increases to the last cervical, inwhich itpresents
the strong quadrate figure which characterizes the same process inthe dorsal vertebræ.
The large canal on each side for the vertebral artery and sympathetic nerve is formed
by the anchylosis of a rudimental rib to the extremities of an upper and lower transverse
process ; the costal process diminishes in size in the anterior cervical vertebræ :it is
wanting inthe dentata, though an arterial canal of very small size is present on each side
of that vertebra. Inthe atlas there are two small inferior transverse processes, but no
canal. The superior or neurapophysial bony arch increases in extent as the cervical
vertebræ approach the head, and inthe third, fourth, and fifthvertebræ this part is perforated
by a small foramen on each side. The spinal chord is least protected by the
vertebræ in the middle of the neck, where there is the greatest extent of motion: there
is a depression on the anterior and posterior parts of the spine in the second, third,
fourth, and in the last six cervical vertebræ.
The length of the cervical region of the spine is 7 inches.
The close resemblance of the Bird to the Reptile in its skeleton is well exemplified in
the young Ostrich, in which even when half-grown the costal appendages of the cervical
region of the vertebræl column continue separate and moveable, as in the Crocodile. I
have already observed that they were anchylosed to the first fifteen vertebræ in the
Apteryx. The first dorsal rib is a slender style about an inch in length ;the rest are remarkable
for their breadth, which is relatively greater than in any other bird;the Cassowaryinthis
respect approaches nearest to the Apteryx. The second, third, fourth, and fifth
ribs articulate with the sternum through the medium of slender sternal portions ;that of
the sixth also reaches the sternum, but is attached only to the sternal rib anterior to it,
and a considerable interspace exists between itsunattached extremity and that of its corresponding
vertebral rib. Inthe first simple and floating rib, the part corresponding to
the head and neck, as usual, is not developed, and itis attached to the transverse process
by the part analogous to the tubercle. Inthe second rib a short and strong cervix,
terminated by a hemispherical head, is given offbelow and in front of the tubercle, and
works in a corresponding socket at the anterior margin of the vertebra. The head and
tubercle, with the points of the vertebræ to which they are attached, intercept large
foramina corresponding to the vertebræl foramina in the cervical region. Immediately
below the tubercle the rib suddenly expands, and then gradually narrows to its lower
end : the neck of the rib increases in length in the third and fourth pairs and diminishes
in the last two;the sixth rib begins to lose its breadth, and the rest become nar-
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