210 ME. W. P. PYCRAFT ON THE MORPHOLOGY AND 



the hinder cervical and thoracic vertebra there is a large aperture beneath the 

 diapophysis, opening in the roof of the tunnel for the vertebral artery, or in the thoracic 

 vertebra below the prezygapophysis and between the dia- and parapophysial articula- 

 tions of the tuberculum and capitulum. The deep fossa at the base of the anterior 

 border of the neural spine of the hinder thoracic vertebrae is here very shallow. 



In Shea the vertebrae have departed still more from the normal type. The cervicals 

 are very long and cylindrical. Neural spines are present only on the 2nd to 5th 

 vertebra. The free hinder borders of the postzygapophyses of the 6th vertebra are 

 received into a pair of shallow pits on the 7th, lying mesio-caudad of the prezyga- 

 pophyses. Cervical ribs are only feebly developed. From the 2nd to 11th vertebras 

 they are represented only by short styliform processes; from this vertebra backwards 

 they are represented only by the extreme anterior articular end of the rib which serves 

 to form the band-shaped external wall of the vertebrarterial canal. As in Struthio, the 

 vertebrarterial canal is roofed by a backward extension of the lamelliform plate 

 depending from the diapophysis and serving as an articulation for the cervical rib. 

 This plate is described and figured as the " rudimentary rib " by Mivart [63] ; 

 doubtless by a slip. 



In Apteryx the form of the atlas and axis vertebras bears some resemblance to 

 Bromceus. The rest of its vertebras differ conspicuously from those of the forms 

 herewith associated. The neural spines never bifurcate. On the anterior vertebras 

 they form compressed blades from the Sth to the 12th ; they are columnar and 

 vertical in form and central in position with regard to the neural laminas. The 

 diapophyses of the 6th and 7th vertebras project outwards and backwards beyond 

 the level of the prezygapophysis; from the 7th to the loth backwards and down- 

 wards ; from this vertebra caudad they project directly outwards, and merge gradually 

 into the transverse processes of the thoracic vertebras. The neural spines of the 

 thoracic vertebras are equal in size, of great breadth antero-posteriorly, and interlock 

 along the dorsal ridge by anterior and posterior bifurcations as in many Neognathce. 



There are no pneumatic apertures in either cervical or thoracic vertebras. Cervical 

 ribs are vestigial. 



In Crypturi the thoracic vertebras are anchylosed and bear hypapophyses. In the 

 Palceognathw these occur only on the posterior cervicals (cervico-thoracic). The 

 penultimate is free, the ultimate fused with the synsacrum. The interzygapophysial 

 ridge is perforated by pneumatic apertures. In the cervical vertebras pneumatic 

 apertures open into the roof of the vertebrarterial canal. 



The diapophyses of the cervicals project forwards beyond the prezygapophyses. 

 The neural arch is constricted in the middle, immediately behind the prezygapophyses. 



The vertebras of Binornis resemble those of Casuarius. The fossas lying beneath 

 the transverse process of the thoracic vertebras, absent in Bromceus, were much larger 

 relatively than in Casuarius. The cervicals resembled those of some species of 



