46 MR. ST. GEORGE MIVART ON THE 
and inconspicuous; a conspicuous fossa on either side of preaxial part of neural spines 
either of the cervical or else of the dorsal vertebra; sacral vertebrae plainly distinct 
from sacro-caudal vertebre ; ilium and ischium united or not; postaxial part of ilium 
not bent much ventrad ; interobturator processes meeting ; ischium joins pubis; either 
an ischiatic or a pubic symphysis; ischium not diverging much yentrad from ilium ; 
marked ilio-pectineal processes; ischium not broad; pubis not very slender ; skeleton 
of tail not broadening out medianly; sacrum narrow ; distal articular surfaces of sternal 
ribs each in two parts; coracoid-grooves large; lips of each coracoid-groove subequal ; 
no median sternal preaxial process. 
CHARACTERS OF STRUTHIO. 
Total number of vertebrae fifty-six ; cervical vertebrae seventeen; vertebrae with ribs 
ten; no lumbo-sacral vertebrie ; sacro-caudal vertebre eight; preaxial 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 vertebra 
small but not obsolete; no neural spines bifurcating laterally; no neural spines 
aborted ; hypapophysis developed from the eighteenth (first cervico-dorsal) to the 
twenty-first (first dorsal) vertebra; hypapophyses but little produced preaxially; a 
conspicuous fossa on each side of preaxial part of neural spines of dorsal vertebra, 
but not of cervical; cervical ribs long and styliform ; dorsal and dorso-lumbar neural 
spines but little axially extended, but considerably extended dorso-ventrally and not 
subequal in height; sacro-caudal vertebra not at all raised dorsad of acetabula, but 
rather depressed ventrad; sacro-caudal vertebra perfectly ossified; sacral vertebrae 
plainly distinct from sacro-caudal vertebre; no lumbo-sacral vertebrae; caudal ver- 
tebre ten; pygostyle a laterally compressed plate; ilium and ischium not united ; 
supratrochanteric fossa not sharp and conspicuous, and placed somewhat postaxiad of 
antitrochanteric process; ischium joins pubis, but not at distal end of latter; no 
ischiatic symphysis; ischium extends a little postaxiad of ilium; pubis extends post- 
axially considerably beyond ischium, as well as ilium; a pubic symphysis; acetabula 
not ventrad of vertebral column, so that the acetabula cannot at all be seen through 
when opposite each other; ribs moderately wide, curvature as described ; complete ribs 
five ; uncinate processes three, their distal ends bent at nearly a right angle to their 
proximal parts; sternum about as long as broad; coracoid-grooves approximated, pre- 
axial margin convex, but with no prominent median process, costal angles moderate, 
five costal articular surfaces in each pleurosteon. 
CHARACTERS OF RHEA. 
Total number of vertebra forty-nine ; cervical vertebrae fourteen; vertebrae with ribs 
nine; sacro-caudal vertebre nine ; three or four lumbo-sacral vertebre ; preaxial articular 
