1903.] OSTEOLOGY OF THE CUCULIFORMES. 285 
up the shaft, and has the glenoid articular surface conspicuously 
laterally compressed and twisted, so as to cross the long axis of 
the shaft transversely. This limb may be readily distinguished 
from that of the Psittaci, inasmuch as in the latter the trochles 
of D. IT. stands out at right angles to the tarso-metatarsal shaft, 
whilst the trochlea for D. IV. has rotated so that its articular 
surface is turned to look directly backwards. Thus, the outer 
condyle comes to lie next the shaft, and, furthermore, is produced 
into a hook-shaped process of considerable size. 
Amongst the Coraciiformes, probably the pelvie limb of Zepto- 
soma most nearly resembles that of the Cuculiformes, but the 
conspicuously higher position on the shaft of the trochlea of D.TV., 
which obtains in this last group, is sufficient to prevent confusion. 
The fibular ridge is confined to the upper end of the shaft, and 
increases in depth from above downwards. 
The length of the fibula may vary considerably even in different 
species of the same genus. Usually it is greatly reduced, but in 
Centropus toulou, for example, it extends considerably beyond the 
middle of the tibial shaft, whilst in C. madagascariensis it falls 
considerably short of this. 
In Crotophaga, Kudynamys, and Rhopodytes it barely extends 
beyond the level of the tibial fibular ridge. 
The cnemial crests are, as a rule, feebly developed, indeed only in 
Geococcyx do they attain to any respectable size. In this species 
the entocnemial crest is more or less quadrate in form; its outer 
border is convex, its inferior concave. The ectocnemial crest is 
triangular in form, and terminates in a small pointed process 
immediately in front of the head of the fibula. 
The shaft of the tibia is long, slender, and cylindrical, and bowed 
slightly forwards. In Geococcyx the posterior lateral borders of 
the internal mesotarsal condyle are produced backwards and 
upwards to form a rather prominent spur. 
The popliteal fossa of the femur is obsolete. 
The pelvic limb of the Musophagi is less specialised in some 
respects than that of the Cuculi. This is especially marked in the 
character of the tarso-metatarsus. As in the Cuckoos, the hypo- 
tarsus is complex, and the tarso-metatarsal shaft grooved in front ; 
but the arrangement of the distal trochlez is of a less specialised 
character, and this fact is especially marked in Schizorhis, the foot 
of which in this respect closely resembles that of Zeptosoma. The 
foot of Schizorhis, however, may readily be distinguished from 
that of Zeptosoma inasmuch as in the latter the trochlea for D. IV. 
bears a very strongly-developed outer lip, which is produced 
inwards towards Me.I. In Sehizorhis this trochlea is almost 
indistinguishable from that of an ordinary eleutherodactyle foot. 
In Turacus, however, the form of the outer trochlea nearly 
resembles that of the Cuculi, but is less markedly compressed, 
and looks backwards and slightly inwards, instead of being twisted 
so as to cross the shaft transversely. Moreover, it is not raised 
high up on the shaft as in the Cuckoos. 
