254 



fourth, fifth and sixth dorsal vertebrae are slightly anchylosed together by the contiguous 

 edges of their spinous processes ; the seventh, eighth and ninth are overlapped by the iliac 

 bones ; but notwithstanding this partial anchylosis, the synovial articulations, both between 

 the bodies and oblique processes, are retained in all the dorsal vertebra;, and a slight, yielding, 

 elastic movement is permitted between those vertebrae. The breadth of the bodies of the dor- 

 sal vertebrae diminishes, and their length increases very gradually from the first to the fourth ; 

 thence the bodies become broader and shorter in the same degree to the sacrum. A short 

 obtuse process is sent off obliquely forwards from the inferior surface of the body of each of 

 the first four dorsal vertebrae ; the corresponding surface of the succeeding ones is smooth and 

 slightly concave from side to side. The articulation between the bodies is by the adaptation of 

 a surface slightly concave in the vertical and convex in the transverse direction at the poste- 

 rior end of one vertebra to opposite curves at the anterior end of the succeeding one. Close 

 to the anterior surface on each side there is a hemispherical pit for the reception of the round 

 head of the rib : this articular pit is supported on a process representing the inferior trans- 

 verse process, except in the three middle dorsal vertebrae. The transverse processes are 

 broad, flat, and square-shaped, with the anterior angle obliquely cut off to receive the abut- 

 ment of the tubercle of the rib, except in the second and third, in which a small process is 

 sent down for the same purpose from the under surface of the transverse process : the trans- 

 verse processes of the last three dorsal vertebrae abut against the under or inner surface of the 

 ilia, and are probably anchylosed thereto in old birds. The nerves issue from the interspaces 

 of the vertebrae above the articulation of the heads of the ribs. The spinous process arises 

 from the whole length of the arch of each vertebra ; it is truncate above, and with the ex- 

 ception of the first, is of the same breadth throughout : all the dorsal spines are much com- 

 pressed, the middle ones being the thinnest, slightly expanding at their truncate extremities, 

 especially the three anterior ones, the first spine being notched behind to receive the con- 

 tiguous angle of the succeeding one : below this there is a considerable interval between these 

 two spiues, but the rest of the spines are in contact throughout, and are probably more anchy- 

 losed in older birds than the specimen here described. 



The first four sacral vertebrae send outwards parapophyses which abut against the ilia, and 

 progressively increase in length and thickness. The breadth of these vertebrae also gradually 

 increases ; but it diminishes in the four succeeding vertebrae, in which the parapophyses are 

 wanting : then the ninth and tenth sacral vertebrae send outwards each a pair of strong par- 

 apophyses to abut against the inner surface of the ossa innominata immediately behind the 

 acetabulum : the anchylosis of the bodies is continued through the four succeeding vertebrae, 

 which are of a very simple structure, devoid of transverse or oblique processes, becoming gra- 

 dually more compressed and more extended vertically, so as to appear like mere bony laminae ; 

 the line of the articulation between the bodies of these posterior sacral vertebrae is obvious, 

 but their spines coalesce to form a continuous bony ridge, which is closely embraced by the 

 posterior extremities of the innominata. The foramina for the nerves are pierced in the sides 

 of the bodies of the sacral vertebrae ; they are double in the anterior ones, but single in the 

 posterior compressed vertebrae, where they are seen close to the posterior margin. 



There are nine caudal vertebrae, which are deeper, and project farther below the posterior 

 portions of the iliac bones than in the other Struthious birds : these vertebrae, as they de- 



