Zoological Society. 345 



by a description of the general structure and peculiarities of its os- 

 seous system. 



The bones of the Apteryx are not perforated for the admission of 

 air, nor do they exhibit the pure white colour which characterizes the 

 skeleton in other birds ; their tough and somewhat coarse texture 

 resembles rather that of the bones of the lizard tribe. 



The spinal column was found to consist of 15 cervical and 9 dorsal 

 vertebra, and 22 in the lumbar, sacral, and caudal regions. The third 

 to the sixth, inclusive, of the dorsal vertebrae, are slightly anchylosed 

 together by the contiguous edges of their spinous processes ; but Mr. 

 Owen supposes that notwithstanding this awc%/o52>, a yielding, elastic 

 movement may still take place between these vertebras. 



The cervical vertebra: present all the peculiarities of the type of 

 Birds ; the inverted bony arch for the protection of the carotid ar- 

 teries, is first seen developed from the inner side of the inferior trans- 

 verse processes of the twelfth cervical vertebra, but the two sides of 

 the arch are not anchylosed together. 



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

 Apteryx. In its small size, and in the total 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. 



After concluding the description of the osteology of the Apteryx, 

 of which the preceding is an abstract, Prof. Owen proceeded to ob- 

 serve, " that so far as the natural affinities of a bird are elucidated by 

 its skeleton, all the leading modifications of that basis of the organi- 

 zation of the Apteryx connect it closely with the struthious group. 

 In the diminutive and keel -less sternum it agrees with all the known 

 struthious species, and with these alone. The two posterior emar- 

 ginations which we observe in the sternum of the Ostrich are present 

 in a still greater degree in the Apteryx ; but the feeble development 

 of the anterior extremities, to the muscles of which the sternum is 

 mainly subservient, as a basis of attachment, is the condition of a 

 peculiarly incomplete state of the ossification of that bone of the Apte- 

 ryx ; and the two subcircular perforations which intervene between 

 the origins of the pectoral muscle on the one side, and those of a 

 large inferior dermo- cervical muscle on the other, form one of seve- 

 ral unique structures in the anatomy of this bird. We have again 



