268 
MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
posteriorly by its mesial border with external border of the combined vomer 
and pterygoid; vorer of great length, continued forwards beyond the 
free end of the parasphenoidal rostrum; pterygoid laminate; orbital 
process of quadrate decurved and articulating with the pterygoid at its 
base; anterior palatine foramen very small, and lying near the tip of the 
beak beyond the vomer; anterior narial and lachrymo-nasal fosse, in 
dried skull, confluent ; mesethmoid with a truncated anterior border ; 
nasal process of premaxilla rod-shaped ; nasal with a vestigial external 
process. 
a’, Vomer expanded into a broad flattened plate between the maxillo- 
palatines, and separated from the parasphenoidal rostrum; beak 
dorso-ventrally depressed ; palatine fenestrated posteriorly, not anchy- 
losed with pterygoid; horizontal plate of mesethmoid appearing on 
the surface of the skull between nasals, but never inflated to form a 
casque ; lachrymals fusing with nasals and frontals ; with long supra- 
orbital processes 
!, Vomer only very slightly erreniiea bebween ihe sasitilloe palestine’ Weak 
laterally compressed ; palatine unfenestrated and anchylosed with the 
pterygoid and vomer; horizontal plate of mesethmoid, nasals, and 
more or less of frontals inflated to form a casque, sometimes of great 
size ; quadrato-jugal fossa not extending forwards to level of antorbital 
plate 
6. Vomer large, ote Peirea, Rese Sade the par aaphensidal rostrum ; 
distal end of pterygoid and hinder end of vomer hidden (in ventral aspect 
of skull) by the palatine which underlies them; pterygoid rod-shaped. 
c!. Vomer deeply cleft anteriorly, exposing the parasphenoidal rostrum 
between a pair of long spurs; anterior palatine foramen long and 
slit-like. 
a", Lachrymo-nasal fossa bounded anteriorly by a bony spike rising 
upwards from the middle of the external border of maxillo-palatine ; 
with large post-orbital processes ; orbital process of quadrate very 
short, not extending beyond level of articulation with pterygoid ; 
lachrymal with large orbital processes; mesethmoid visible as a 
lozenge-shaped plate between nasals . : ; 
'. Lachrymo-nasal fossa bounded anteriorly by a Auleate fd articu- 
lating above with the nasal and below with the hinder border of the 
maxillo-palatine plate ; no post-orbital processes ; orbital process of 
quadrate moderately long, with a free end projecting beyond articu- 
lation with pterygoid ; lachrymal without orbital processes ; nasal 
schizorhinal; inter-orbital septum cae oe mesethmoid not visible 
on surface of skull 
d'. Yower truncated anteriorly, not eae « so far forward as the aia of 
the parasphenoidal rostrum; anterior palatine foramen small, closed 
by anterior end of parasphenoidal rostrum ; large post-orbital processes ; 
lachrymals fused with frontals and not readily traceable; orbital 
Dromeus. 
Casuarius. 
Rhea. 
Tinamide. 
