288 PROF. OWEN ON THE ANATOMY 
splints, but are quite detached from each other as in Struthious birds. The oblique pro- 
cesses offer no peculiarity; a process is continued backwards from the upper part of 
those belonging to the first and second dorsal vertebre. The spinous process arises from 
the whole length of the arch of each vertebra ; it is truncate above, and with the excep- 
tion of the first, is ofthe same breadth throughout : all the dorsal spines are much com- 
pressed, the middle ones being the thinnest, slightly expanding at their truncate ex- 
tremities, especially the three anterior ones, the first spine being notched behind to 
receive the contiguous angle of the succeeding one: below this there is a considerable 
interval between these two spines, but the rest of the spines are in contact throughout, 
and are probably more anchylosed in the older birds than was observed in the specimen 
here described. The length of the dorsal region of the spine is 4 inches. 
The length of the vertebral column behind the dorsal vertebre included between the 
ossa innominata is 3 inches. The first four sacral vertebre' send outwards inferior 
transverse processes which abut against the ilia, and progressively increase in length 
and thickness. The breadth of these vertebre also gradually increases ; but it diminishes 
in the four succeeding vertebre, in which the inferior transverse processes are wanting : 
then the ninth and tenth sacral vertebre send outwards each a pair of strong inferior 
transverse processes to abut against the inner surface of the ossa innominata immediately 
behind the acetabulum: the anchylosis of the bodies is continued through the four suc- 
ceeding vertebre, which are of a very simple structure, devoid of transverse or oblique 
processes, becoming gradually more compressed and more extended vertically, so as to 
appear like mere bony lamine ; the line of the articulation between the bodies of these 
posterior sacral vertebre is obvious, but their spines coalesce to form a continuous bony 
ridge, which is closely embraced by the posterior extremities of the znominata. The 
foramina for the nerves are pierced in the sides of the bodies of the sacral vertebre ; 
they are double in the anterior ones, but single in the posterior compressed vertebre, 
where they are seen close to the posterior margin. 
There are nine caudal vertebre, which are deeper, and project farther below the pos- 
terior portions of the iliac bones than in the other Struthious birds: these vertebre, as 
they descend, progressively increase in lateral and diminish in vertical extent ; the spinal 
canal is continued through the first five, and they are all moveable upon each other, 
excepting the two last, which combine to form a vertebra analogous to the expanded 
terminal vertebra in other birds, but which here exceeds the rest only in its greater 
length, and gradually diminishes to an obtuse point. In the Ostrich the corresponding 
vertebra is expanded for the support of the caudal plumes, but in the Apteryz it offers 
the same inconspicuous development as in the Rhea and Emeu. 
The cervical vertebre present all the usual ornithic peculiarities. Their general form 
and proportions are shown in the figure (Pl. LIV.). The single inferior process for the 
attachment of the complicated longus colli anticus is present in the three last vertebre. 
' See Pl. LV. 
