32 MR. W. P. PYCRAFT ON THE | May 2, 
the base of the beak it expands considerably and is supported from 
within by outstanding antorbital plates. Lachrymals, except in 
Calyptomena, are absent, and consequently take no share in the 
formation of the preor bital region of the skull. In this particular 
the Kurylemide agree with the bulk of the Passeres, in which, 
however, vestiges of the lachrymal are frequently present. 
The Re ontalsy terminate abr uptly i in front, not extending beyond 
the level of the anterior border of the mesethmoid. The nasals 
and nasal-processes of the premaxilla are also sharply truncated 
caudad ; thus, at their meeting with the frontals and mesethmoid 
a freely moving nasal hinge is formed (Pl. IT. figs. 26, 3a, 4). 
The incipient stages in the development of such a hinge can be 
studied in Chasmor hynchus—one of the Cotingide. 
The Base of the Skull. 
The basitemporal plate is shghtly hollowed in the middle line, 
and is continued forward for some distance on to the parasphenoidal 
rostrum; owing to the small size of the brain its free edge 
projects beyond the level of the brain-case. To appreciate this 
point the skull of one of the Eurylemidz should be compared 
with say that of Menwra or Corvus, where, it will be found, the 
basitemporal plate fails to conceal the brain-case when the skull is 
seen from below. The edge of this plate is free only at its apex. 
Not even vestiges of the basipterygoid processes remain. 
The parasphenoidal rostrum is long and slender. 
The occipital condyle is spherical and depends from the roof of 
a shallow pre-condylar fossa. 
The Lateral Aspect of the Cranium. (Pl. IT. fig. 2.) 
The tympanic cavity is small, shallow, and has little or no floor, 
The constriction of the skull-wall in the temporal region, to form 
the “temporal fosse,” gives the tympanic cavity the appearance of 
the aperture of a tube, the cylinder of which is formed by the 
‘¢squamosal prominence” and lateral occipital wing. 
The roof of this cavity is formed by the under “surface of the 
processus 2 gomaticus squamosi. Its floor in part by the lateral 
occipital wing and in part by the ossification of tissue extending 
between this wing and the external angles of the basitemporal 
plate; but this region is much cut away. 
Within the cavity three apertures will be found in the dried 
skull after the removal of the tympanic membrane. The largest 
of these is the mouth of the recessus tympanicus anterior. 
Immediately outside this, and below the otic articular surface for 
the quadrate, is the fenestral recess : this is very small, and neither 
the fenestra ovale nor the rotunda can be distinguished within it, 
though the columella is in position above; and behind the fenestral 
recess a cluster of minute pneumatic apertures will be found, 
corresponding to a similar group commonly found in the higher 
