AXIAL SKELETON OF THE STRUTHIONID^. 47 



surface of atlas with only a minute dorsal notch ; no hyperapophyses to atlas ; hypapo- 

 physis of axis not veiy large ; neural spine of axis not very high ; hyperapophysis of 

 axis well developed ; neural spines of cemcal vertebrae almost obsolete ; those of fourth 

 to seventh vertebrae abort ; neural spines of thirteenth to sixteenth vertebra bifurcate 

 laterally ; hypapophysis developed from the last cervical to the second dorsal vertebra ; 

 hypapophyses narrow and preaxially produced; a conspicuous fossa on each side of 

 preaxial part of neural spiues from the twelfth to the fifteenth inclusive ; cervical ribs 

 short and not styliform; dorsal and dorso-lumbar neural spines rather much axially 

 extended and subequal in height, but not nearly as in Apteryx ; sacro-caudal vertebrae 

 raised quite dorsad of acetabula, also very imperfectly ossified ; sacral vertebrae plainly 

 distinct from sacro-caudal vertebrae ; caudal vertebrae only five ; pygostyle very small 

 and cylindrical ; ilium and ischium united, but not at distal end of ischium ; supratro- 

 chanteric process sharp and conspicuous, placed preaxiad of the antitrochanteric pro- 

 cess ; ischium joins distal end of pubis ; an ischiatic symphysis ; ischium extends much 

 postaxiad of ilium ; pubis extends nearly as much postaxiad as does ischium ; no pubic 

 symphysis; acetabula completely ventrad of vertebral column, so that both can be 

 entirely seen through when opposite each other; ribs moderately wide, curvature 

 diflerent from that of Strufhio; complete ribs only three; uncinate processes three, 

 very long ; sternum decidedly longer than broad, coracoid-grooves not approximated, 

 preaxial margin a shallow concavity, costal angles rather long, three costal articular 

 surfaces in each pleurosteon. 



CHAKACTERS COMMON TO DEOM^US, CASUABIUS, AFTERYX, 



AND DINOBNIS. 



Hyperapophyses of axis well developed ; cervical vertebrae short ; cervical diapophy- 

 sial lamella3 large and conspicuous ; at least one lumbo-sacral vertebra ; sacro-caudal 

 vertebrae more or less raised above ventral margin of acetabula, but not above entire 

 acetabula; sacro-caudal vertebrae well ossified; ilium and ischium not united post- 

 axially'; ischium and pubis uniting distally or not; no ischiatic or pubic symphysis; 

 no great difi'erence between the postaxial extensions of ilium, ischium, and pubis ; 

 acetabula more or less seen through when opposite ; distal articular surfaces of sternal 

 ribs single ; no prominence on ventral surface of sternum. 



CHAEACTERS COMMON TO BROM^US AND CASUARIUS. 



Hyperapophyses of atlas moderate ; neural spine of axis rather high ; hyperapophyses 

 of axis well developed ; cervical vertebrae rather short ; neural spines of cervical vertebrae 



' Save Bometimes in Casuarius. 



