56 R. W. SHUFELDT, 
terminates in a distinet, elongate tubercle, corresponding to an 
“external malleolus”. 
The characters of the tibio-tarsus in Dranta agree with the 
corresponding ones in Dendrocygna. 
In Chen the cnemial crests are somewhat reduced, and do not 
rise so much above the shaft’s summit as is usually seen among 
the Anseres. The fibular ridge in the genus is thick and short 
and placed high up on the tibio-tarsal shaft. 
Apart from the matter of size — the swan’s being much the 
larger of course — the tibio-tarsus and fibula in Olor agree 
very well with those bones as I have described them for Dendro- 
cygna. 
In Charitonetta albeola the cenemial processes of the tibio- 
tarsus take on a form somewhat resembling the form they assume 
in some of the smaller grebes, only the combined process in the duck 
is not so lofty, — though for a duck, its enemial process, on either 
side, is extended notably above the summit of the bone from which 
it projects, — the ectocnemial and endocnemial processes meeting, 
proximally, at a common point. This is also true of Olangula 
(Osteology of Birds, p. 302), in which genus the processes „are 
carried up in such a manner as almost to rival the grebe in this 
particular, having very much the same form.“ 
As compared with the rest of the skeleton of the pelvic limb, 
the tarso-metatarsus in Dendrocygna autumnalis (454) is unus- 
ually long and stout, and, proportionately, notably more so than in 
D. bicolor. On the internal lateral border of its summit it sends 
up quite a conspicuous process, which, in the articulated limb, is 
applied to the inner side of the internal condyle of the tibio- 
tarsus. 
Low, short, and bulky in form, the hypotarsus is 4-times 
longitudinally grooved for the passage of the tendons passing down 
behind the shaft for insertion below. The outer groove is shallow 
and short, while the inner one is largely overarched by the inner 
side of the hypotarsus rising up and curling over it. 
Anteriorly, the shaft is concaved longitudinally above; while 
posteriorly it is flat and marked by three longitudinal ridges running 
down its entire length, for the better guidance of tendons. 
The distal trochleae are large, especially the central one, 
which is placed much the lowest on the shaft; next comes the outer 
one, while the elevated small internal one is placed posteriorly and 
