264 MR. W. P. PYCRAFT ON THE [Mar. 17, 
limb with the outer border of the palatine. Its further relations 
with the lachrymal will be discussed presently. 
The nasal septum is completely ossified, and the external nares 
are In consequence imperforate. The ectethmoidal region presents 
several points for comment. By the ossification of the alinasal 
wall, the form of the external nares is greatly changed in many of 
the Cuculi. In consequence of this ossification, the space between 
the premaxillary and descending processes of the nasal becomes 
obliterated. Thus in Geococcyx the nostrils take the form of 
an oval aperture lying just cephalad of the middle of the beak. 
In Rhamphococcyx this aperture is still further reduced, and 
consists only of an elongated slit lying at the base of the beak 
above the tomium. In /hinococcyx the aperture is nearly circular 
at the base of the beak, and bounded by a deep groove in front. 
The alinasal ossification 1s, however, imperfect, inasmuch as a 
small round hole is left in the angle between the premaxillary 
and descending processes of the nasals. In TVaccocowa this 
superior foramen and the aperture of the nostril have blended. 
In Cowa the floor of the anterior region of the nasal fossa is 
raised up into a sharp longitudinal ridge. 
In the Musophagi the form of the external nostril differs con- 
spicuously from that of the Cuculi. It is situated slightly distad, 
or proximad, of a line passing through the middle of the beak, and 
is reniform mm shape. In Zwracus it hes distad, in Schizorhis 
proximad of the middle line. In both genera, just within the 
mouth of the aperture, lies a well-developed concha vestibulum. 
This is especially large in Schizorhis. Furthermore, the genus is 
peculiar in that immediately distad of the concha the nasal septum 
is pierced by a minute foramen. 
The Cranial Cavity.—The metencephalic fossa is somewhat 
shallower in the Musophagi than in the Cuculi. The internal 
auditory meatus in the Cuculi is sharply defined, strongly con- 
trasting in this respect with the Musophagi, in which it is but 
ill-defined. The vagus foramen, which lies caudad and ventrad of 
the meatus, is small. The orbito-nasal foramen (v') pierces the 
outer superior rim of the fossa near the outer angle of the dorswm 
sell. 
The cerebellar fossa is relatively smaller in the Cuculi than in 
the Musophagi, and in both it is relatively smaller than in many 
other groups, ¢. g. Falconiformes. In the Cuculi the floccular 
fossa is very shallow, and lodges a deep slit-like vertical 
depression. In the Musophagi this fossa is reniform, deeper, and 
lodges a deep and wide depression which gives the reniform 
character to the whole. 
The mesencephalic fossa is fairly sharply defined in both groups. 
Among the Cuculi, this is especially noticeable in Geococcyx. Its 
floor, in both groups now under consideration, is pierced by the 
trigeminal foramen. The difference in position of this foramen is 
worth noticing. In the Falconiformes it lies, together with the 
orbito-nasal (v'), in a pit carved out of the superior border of 
