PHYLOGENY OF THE PAL.EOGNATH^E AND NEOGNATH^l. 271 



B. Vertebrae (not including Crypturi) 1 . 

 All the pre-synsacral vertebra? are heterocoelous and free ; all the synsacral vertebrae develop 

 high neural spines ; intercentra are wanting. 



A. Hyperapophyses of axis well developed; cervical vertebras short; cervical 

 diapophysial lamella? large and conspicuous ; at least one lumbo-sacral 

 vertebra ; sacro-caudal (post-sacral) vertebrae well ossified. 



a. Hyperapophyses of atlas moderate; neural spine of axis rather high; 



hyperapophyses of axis well developed ; cervical vertebra? rather short ; 

 neural spines of cervical vertebrae well developed and greatly excavated 

 postaxially ; no neural spines laterally bifurcating ; catapophyses com- 

 mence at about the sixth vertebra, and do not form a ring ; hypapophyses 

 well developed, not much produced postaxiad; diapophysial lamella 

 extending towards postzygapophysis, large and conspicuous ; cervical 

 ribs moderately long and styliform ; thoracic and lumbar neural spines 

 not much axially extended, and not subequal in height ; post-sacral 

 vertebrae raised in part, more or less, above ventral margins of acetabula; 

 sacral vertebrae not plainly distinct from post-sacrals ; sacral and post- 

 sacral neural spines laterally expanded and separating the post-acetabular 

 ilium ; caudal vertebra? eight or nine ; pygostyle cylindrical. 

 a'. Total number of vertebrae fifty-four ; cervical vertebrae seventeen or 

 eighteen; vertebrae with ribs nine; post-sacral vertebrae nine or ten; 

 pre-axial articular surface of atlas moderately notched dorsally ; hypa- 

 pophysis of axis much elongated; hypapophyses developed from the 

 eighteenth or nineteenth to the twenty-third vertebra ; a conspicuous 

 fossa on each side of the pre-axial part of the neural spines of dorsal 

 vertebra? ; post-sacral vertebra? raised decidedly dorsad of ventral 



margins of acetabula Drommis. 



b'. Total number of vertebrae from fifty-five to fifty-nine ; cervical vertebrae 

 fifteen or fourteen ; vertebrae with (free) ribs eleven or twelve ; sacro- 

 caudal (post-sacral) vertebrae eight or nine; pre-axial articular surface 

 of atlas moderate, may become a foramen ; hypapophysis of axis 

 extremely long; hypapophyses developed from eighteenth to twentieth 

 vertebra ; fossa? beside pre-axial part of neural spines very small ; sacro- 

 caudal (post-sacral) vertebra raised scarcely at all dorsad of acetabula . Casuarius. 



b. Hyperapophyses of atlas large ; neural spine of axis lofty ; hyperapophysis 



of axis moderate or extremely large ; cervical vertebra? short ; neural 

 spines of cervical vertebrae generally more or less well developed ; cata- 



resembles D. irroratus. In the conspicuous development of the cerebral dome it differs from both existing 

 species. 



I would remark here that the specific characters attributed to D. irroratus are based upon an examination 

 of a single unnamed skull in the British Museum Collection ; but these appeared to me to be sufficiently 

 marked to justify my determination of this skull as of D. irroratus. 



1 This Key is compiled, with modifications, from Mivart's memoir. 



2p2 



