272 ME. W. P. PYCEAFT ON THE MORPHOLOGY AND 



pophyses may form a ring ; diapophysial lamella extending towards 

 postzygapophysis, large and conspicuous or extremely so ; cervical ribs 

 moderate or small ; sacro-caudal (post-sacral) slightly raised dorsad of 

 ventral margin of acetabulum ; cervical vertebrae fifteen. 

 c'. Total number of vertebrae from forty-five to forty-seven ; post-synsacral 

 vertebras three ; pre-axial articular surface of atlas scarcely at all 

 notched dorsally ; hyperapophyses very long ; a minute hypapophysis 

 to atlas ; no hypapophysis to axis ; neural spine of axis very high ; 

 hyperapophysis of axis extremely large ; catapophyses commence at 

 the fifth vertebra, in the tenth and eleventh vertebrae they form a 

 ring ; hypapophyses developed from the twelfth cervical to the third 

 thoracic vertebra; diapophysial lamella extremely large and con- 

 spicuous, developing conspicuous postaxially extending processes ; 

 cervical styliform ribs small ; thoracic and lumbar neural spines 

 exceedingly extended axially and subequal in height ; synsacrum with 

 sacral vertebrae plainly distinct from post-sacral ; post-sacral bent much 

 ventrad of ilia ; free caudal vertebrae seven or nine; pygostyle conical. Apteryx. 

 d'. Hyperapophyses of axis moderate; neural spines of cervical vertebrae 

 well developed and deeply excavated postaxially ; neural spines of 

 fourth, fifth, sixth, and seventh cervical vertebrae bifurcating laterally ; 

 catapophyses commencing at the fourth vertebra; hypapophyses 

 commence at fifteenth (last cervical) vertebra; diapophysial lamella 

 extending towards postzygapophysis, large and conspicuous ; cervical 

 ribs probably moderately long and rather styliform; thoracic and 

 lumbar neural spines not much axially extended, and probably not sub- 

 equal in height ; synsacrum with post-sacrals not bent ventrad of ilia. Dinar nithida:. 

 B. Axis vertebra with a hypapophysis, with or without well-developed hyper- 

 apophyses ; cervical vertebrae greatly elongated ; neural spines of cervical 

 vertebras small or almost obsolete ; catapophyses commencing about the 

 sixth vertebra; catapophysis never forming a ring; diapophysial lamella 

 extending towards posterior zygapophysis, small and inconspicuous ; a 

 conspicuous fossa on either side of pre-axial part of neural spines either of 

 cervical or thoracic vertebrae ; synsacrum with sacral vertebras plainly 

 distinct from post-sacral vertebrae. 

 e'. Total number of vertebrae fifty-six ; cervical vertebrae seventeen ; vertebras 

 with ribs ten ; no lumbo-sacral vertebrae ; synsacrum with eight post- 

 sacral vertebras ; pre-axial articular surface of atlas with a large dorsal 

 notch ; hyperapophyses of atlas moderate ; hypapophysis of axis rather 

 small ; neural spine of axis moderate ; neural spines of cervical vertebrae 

 small, but not obsolete ; no neural spines bifurcating laterally ; no 

 neural spines aborted ; hypapophyses developed from the eighteenth 

 (first thoracico-dorsal) to the twenty-first (first thoracic) vertebrae ; 

 hypapophyses but little produced pre-axially ; a conspicuous fossa on 

 each side of pre-axial part of neural spines of thoracic vertebrae, but not 

 of ceiwical ; cervical ribs long and styliform ; thoracic and thoracico- 



