188 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
‘length into two slender rods grooved dorsally; in C. bennetti only about one-fourth is so 
divided: the cleft not extending more than half the distance of the posterior nares, in 
the other forms it is continued forwards beyond this point. C. c. australis differs from 
both types, the cleft of the vomer being rather less than half the total length and 
terminating in the region of the anterior end of the posterior narial aperture. 
Anteriorly the vomer becomes laminate and wedged in between the maxillo-palatine 
processes, and passing forwards rests upon the palatine processes of the premaxilla. 
The palatine foramen by the great forward extension of the vomer is almost obliterated. 
In a ventral view—before complete anchylosis has taken place—the feet of the 
vomer appear to be wedged in between the pterygoid and palatine. Removal of this 
latter, or a dorsal view, however, reveals the true relations of these parts. It will then 
be seen that the right and left limbs are closely applied to the external ventral border 
of the twisted pterygoid, extending backwards to a point very near its middle. The 
pterygoid can be traced forwards along the mesial border of the vomer as a slender 
spike for some considerable distance. On a dorsal view, the right and left grooved 
limbs of the vomer are well displayed, and show that each has been twisted outwards 
so that its inner free border comes to look dorsally, and the latter ventrally. The 
flattened surface of this twisted region is closely applied to the ventral surface of the 
anterior end of the pterygoid, so that vomer and pterygoid form one common rod 
articulating with the quadrate. The dorsal border of the twisted end of the vomer is 
slightly thickened and, traced backwards, trends downwards beneath the outer border 
of the pterygoid. From the vomer backwards, the sutural surface is continued as a 
shallow groove along the outer ventral border of the pterygoid, terminating at the 
level of the basipterygoid processes. It is this ventral union of palatine and 
pterygoid that gives the impression that the vomer is wedged in between these two 
bones, when the skull is viewed from this surface. 
In Dromeus (Pl. XLII. fig. 7) the “feet” of the vomer extend forwards for about 
one-third of its total length. Anteriorly it expands into a broad oval plate tapering 
again forwards to terminate, as in Caswarius, near the body of the premaxilla. The 
maxillo-palatine process overlaps the distal end dorsally; the palatine processes 
underlie it ventrally. Its relations with the pterygoids and palatines posteriorly are 
precisely similar to those which obtain in Casuarius. As a matter of fact, it should be 
remarked, the palate of Dromeus is even simpler in type than in Casuarius, and 
consequently represents, as we shall see, the simplest arrangement of these bones of 
all the Palwognathe. 
After these, the simplest palate amongst the remaining Paleognathine forms is that 
of Struthio. 
The vomer of Struthio (Pl. XLII. fig. 8) is a degenerate structure. Anteriorly 
it does not extend beyond the middle of the enormous palatine foramen ; posteriorly 
it is cleft, but has entirely lost all connection with the pterygoid, falling short thereot 
