106 



tlie thinnest, slightly expaiiding at their truncate extremities. The 

 length of the dorsal region was four inches. The length of the ver- 

 tebral column behind the dorsal vertebrcB, included betvveen the ossa 

 innominata, was three inches. The first four and the ninth and tenth 

 sacral vertebrce, send outwards inferior transverse processes. The 

 foramina for the nerves are pierced in the base of the arches of the 

 sacral vertebrce ; they are double in the anterior ones, but single in 

 the posterior compressed vertebra, where they are situated close to the 

 posterior margin. The cervical vertebrce present all the peculiarities 

 of the type of Birds ; tlie inverted bony arch for tlie protection of 

 the carotid arteries, is first seen developed from the inner side of the 

 inferior transverse processes of the twelfth cervical verlebra, bnt the 

 two sides of the arch are not anchylosed together. The spinous 

 process is thick and strong in the Vertebra dentata, but progressively 

 diminishes to the seventh, \vhere it is reduced to a mere tubercle ; it 

 reappears at the eleventh, and progressively increases to the dorsal 

 vertebra:. The large canal on each side for the vertebral artery and 

 sympathetic nerA'e, is forraed by the anchylosis of a rudimentai rib 

 to the extremities of an upjjer and lovver transverse process. The 

 spinal chord is least protected by the vertebrce in the middle of the 

 neck, where there is the greatest extent of motion. The length of 

 the cervical region \vas seven inches. 



In the first fifteen vertebrce the costal appendages Avere an- 

 chylosed ; in the nine succeeding vertebrce the ribs appear to re- 

 main permanently moveable ; the first is a slender style a1)0ut an 

 inch in length, the ręst are remarkable for their breadth, which is 

 relatively greater than in any other bird. The second, third, fourth 

 and fiftli ril)s, articulate with the sternum through the niedium of 

 slender sternal portions. The appendages to the vertebral ribs are 

 developed in the second to the eighth inclusive ; they are articulated 

 by a broad base to a fissure in the posterior margin of these vertebral 

 ribs, a llttle below their middle; those belonging to the third, fourth, 

 fifth and sixth ribs, are the longest, and overlap the succeeding rib ; 

 these processes were not anchylosed in the specimen described. The 

 first four sterniU ribs are transversely expanded at their sternal ex- 

 tremities, which severally present a concave surface llned with smooth 

 cartilage and sjTiovial membrane, and playing upon a corresponding 

 smooth convexity in the costal margin of the sternum, \vhich thus 

 ])resents four true enarthrodial joints, \vith capsular ligaments on 

 each side. 



The sternum. is reduced to its lowest grade of development in the 

 Aptcryx. In its small size, and in the totai absence of a keel, it re- 

 sembles that of the struthious birds, but differs in the presence of 

 two subcircular perforations, situated on each side of the middle 

 line, in the wide anterior emargination, and in the much greater ex- 

 tent of the two posterior fissures. The anterior margin presents 

 no trace of a manubrial process, as in the Ostrich, the interspace 

 between the articular cavities of the coracoid being, on the con- 

 trary, deeply concave. The articular surface for the coracoid is au 

 oj)cn groove, externally to \vhich the anterior angles of the sternum 



