286 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
Fig. 6. Ventral aspect of fig. 2, showing the broad vomer and its continuance 
backwards on to the pterygoid. The palatines articulate with the external 
border of the foot of the vomer and external border of the pterygoid. In 
Rhea the articulation between pterygoid and vomer is concealed by the 
palatine. 
Fig. 7. Ventral aspect of fig. 3, showing the vestigial vomer, which does not now 
articulate with the pterygoid. Note the absence of the palatine processes of 
the premaxille. The palatine has fused with the external pterygoid border. 
Fig. 8. Ventral aspect of fig. 4, showing the complete fusion of the vomer, pterygoid, 
and palatine. 
ag 
ADDITIONAL LETTERS. 
ant.b,f. =anterior basi-cranial fontanelle. n.=nasal. 
ant.h.=antrum. 0.c.=occipital condyle. 
b.b.p.=basitemporal platform. pa.=palatine. 
b.p.=basipterygoid processes. pa.r.=parasphenoidal rostrum. 
hy.for.=hypoglossal foramina, 1, 2, 3. p-pmz.=palatine process of premaxilla. 
,=lachrymal. p-p.=paroccipital process. 
Lp.=lachrymo-nasal pillar. pt.=pterygoid. 
Lr. =lambdoidal ridge. $.=supra-orbital bones from lachrymal to 
m.e.=mesethmoid. frontal. 
mx.p.=maxillo-palatine process. v.=vomer. 
n.pmxz.=nasal process of premaxilla. vag.for.=vagus foramen. 
PLATE XLII. 
The immature Skull. 
Fig. 1. Dorsal aspect of the palatine bones of Apteryx mantelli (p. 204), to show the 
sutures, as yet unclosed, between the vomer, pterygoid, and palatine. 
Fig. 1a. Ventral aspect of the same, to show similar sutures. 
Fig. 2. Sagittal section of skull of Apterya australis mantelli, after Parker, for the 
purpose of comparison with Dromeus. Note the appearance of the squamosal 
on the inside of the skull in Apteryx. 
Fig. 3. Ventral aspect of the skull of Hmeus (p. 270), for the purpose of comparison 
with Rhea. Note the similarity in the relations of the pterygoid and vomer. 
Fig. 4. Sagittal section of cranium of embryo Dromeus nove-hollandie, to show the 
separate bones. 
Fig. 4a. Outer view of fig. 4. Note how completely the squamosal conceals and 
protects the pro- and opisthotic bones. In the nestling Penguin the 
squamosal is deeply emarginate posteriorly and exposes the otic bones. 
Fig, 5. Ventral aspect of base of skull of Rhea americana, to show sutures. 
