AXIAL SKELETON OF THE STRUTHIONID#. 47 
surface of atlas with only a minute dorsal notch; no hyperapophyses to atlas ; hypapo- 
physis of axis not very large; neural spine of axis not very high ; hyperapophysis of 
axis well developed; neural spines of cervical vertebree 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 spines 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 vertebree 
raised quite dorsad of acetabula, also very imperfectly ossified ; sacral vertebra plainly 
distinct from sacro-caudal yertebre ; caudal vertebra 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 
different from that of Struthio; 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. 
CHARACTERS COMMON TO DROMAUS, CASUARIUS, APTERYX, 
AND DINORMIS. 
Hyperapophyses of axis well developed ; cervical vertebra short ; cervical diapophy- 
sial lamelle large and conspicuous; at least cne lumbo-sacral vertebra; sacro-caudal 
vertebrze more or less raised above ventral margin of acetabula, but not above entire 
acetabula; sacro-caudal vertebra well ossified; ilium and ischium not united post- 
axially’; ischium and pubis uniting distally or not; no ischiatic or pubic symphysis; 
no great difference 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. 
CHARACTERS COMMON TO DROIAUS AND CASUARIUS. 
Hyperapophyses of atlas moderate; neural spine of axis rather high ; hyperapophyses 
of axis well developed; cervical vertebre rather short; neural spines of cervical vertebrae 
1 Save sometimes in Caswarius. 
