1903.] OSTEOLOGY OF THE CUCULIFORMES. 263 
lachrymal extends backwards for some distance over the frontals. 
In Hudynamys the frontals are deeply notched to receive the 
orbital process of the lachrymal, which is more or less diamond- 
shaped. In other genera the orbital process of the lachrymal 
may be semilunar or rod-shaped. Where the antorbital process 
is very large, the descending process of the lachrymal is always 
more or less markedly degenerate. In Cuculus it has disappeared 
altogether, whilst the orbital process has fused with the frontal 
and nasal bones. In Zanelostomus javanicus it is reduced to a 
mere vestige. The descending process is unusually large in 
Crotophaga, one of the genera, it will be remembered, with a small 
antorbital process. 
Geococcyx has the largest lachrymal of all the Cuckoos. It is 
nearly columnar in form, flattened antero-posteriorly, and deeply 
grooved immediately above the quadrato-jugal bar. 
The lachrymal in the Musophagi in its general shape closely 
resembles that of the Cuculi: the orbital process is, however, 
inclined more upwards. The descending process, judging from 
what obtains in Schizorhis and Musophaga, is fairly strongly 
developed. In Schizorhis the free end of the descending process 
is twisted in itself, rests upon the quadrato-jugal bar, and articu- 
lates by its postero-internal angle with the enormous ossiculum 
lachrymo-palatinum. 
The lachrymo-nasal fossa varies considerably in size. Among 
the Cuculi, it may be described as large in Hudynamys, Centropus, 
Guira, and Crotophaga. In Coua, Rhamphocoecyx, and Geo- 
coccyx, for example, it is extremely reduced by the encroachment 
of the lachrymal. 
The Ethmoidal Region.—The mesethmoid, both in the Cuculi 
and the Musophagi, terminates abruptly immediately in front of 
the antorbital plate. The horizontal plate formed by the expan- 
sion of its dorsal border is but feebly developed. 
The antorbital plate (prefrontal), which, with the lachrymal, 
bounds the orbit in front, is, in some Cuculi, e. g. Cacomantis, 
Centropus, Coua, Coccystes, Cuculus, Hudynamys, Geococcyx, 
Piaya, Taccocoua, and Sauwrothera, conspicuously large, quadr: ite 
in form, and has its dorsal border pierced by two focaiine end 
inner for the passage of the olfactory nerve, and an outer for the 
orbito-nasal (v'). 
In other forms, e. g. Guira, Crotophaga, the antorbital plate, 
though large, has fie exter nal lateral and inferior borders 
deeply, excised. In such cases the orbito-nasal foramen described 
above is represented by a notch. Attached to the inferior border 
of this plate is a vestigial ossiculwm palatinum, which, however, is 
generally wanting in dried skulls. 
In the Musophagi the antorbital plate is greatly reduced, 
forming but a triangular process projecting from the mesethmoid, 
From its inferior border depends a well-developed ossieulum 
lachrymo-palatinum. In Schizorhis this bone is relatively 
enormous, projecting downwards to articulate by a strap-shaped 
