36 MR. W. P. PYCRAFT ON THE [May 2, 
Corydon, Hurylemus, and Cymbirhynchus differ conspicuously 
from Calyptomena in this matter of the narial aperture, as may be 
seen by a comparison of figs. 26, 3a, 4, Pl. IT. 
Tn all three genera the nasal is reduced to its smallest possible 
limits, little more than an arcuate bar being left. Of this, one 
half represents the descending process of the nasal, the other the 
body of the bone,—now merely a rod joined at its inner end to 
the nasal process of the premaxilla, and affording the means of 
articulation with the frontals. This, as I have remarked, takes 
the form of a nasal hinge. In Hwrylemus and Corydon the nasal 
fossa, as in Calyptomena, is open in the dried skull, the actual 
position of the nasal orifice in the living bird being indicated by 
semicircular grooves in the anterior border of the nasal fossa. 
The circle completing the rest of the fossa in the living bird 
was roofed by the alinasal wall. In Cymbirhynchus this wall 
almost completely ossifies, leaving an oval narial aperture, and 
a small semilunar space immediately in front of the nasal (fig. 3 
Pl. IT.). 
In the Kurylemide the floor of the olfactory chamber is open 
behind, revealing in Calyptomena an ossified sheet-like nasal 
septum, which in Corydon becomes immensely swollen. 
In the Coracie, certain Caprimulgi and Pici the floor of the 
olfactory chamber is more or less ossified. In Hurystomaus and 
the Bucconide there is a long palatal fissure, which at first sight 
appears to correspond to the huge palatal cavity of Hurylemus. 
An examination shows, however, that this vacuity leads into a 
spacious cavity underlying the olfactory chamber and formed by 
the inflation and absorption of tissue of the nasal septum. In 
Podargus the palatal surface of the premaxilla is completely 
ossified, and the olfactory chamber is reduced to the smallest 
possible limits. 
In Corydon the nasal process of the premaxilla is immensel 
swollen and rises far above the level of the nasal hinge. The 
frontal is similarly swollen immediately above this hinge. The 
intermediate stages between this condition and that found in 
Calypiomena can be studied in Cymbirhynchus. Corydon, indeed, 
would appear to have reached the high-water mark of speciali- 
sation in the matter of the jaws, among the Eurylemide. 
b) 
The Ma«illo-jugal Arch. 
The maxilla, as usual, is in the adult completely fused with the 
premaxilla. In Corydon the maxillary region of the jaw is highly 
developed and forms a large semicircular plate, the convexity 
forming its free edge and projecting downwards far beyond the 
level of the quadrato-jugal bar. 
The mawillo-palatine processes in Calyptomena take the form of 
a pair of delicate rods projecting backwards at a very marked 
angle from the body of the maxilla, which, at this point, is 
perforated by small pneumatic apertures. These rods, on each 
