i6 
Osteological Studies of the Subfamily Ardeince. 
bones above and below, is subtrikedral in form and devoid of par¬ 
ticular character. 
Showing a considerable transverse dilatation at its proximal 
extremity, the third metacarpal soon quits the shaft of the second, 
to become much smaller and rounder, to be found parallel to it, 
until within a short distance from its lower end, where they are 
again connected by bone. 
At the proximal extremity of this carpo-metacarpus, we find 
a broad trochlear surface, contributed in 
the usual manner by the os magnum , one 
of the carpal bones free in the wrists of 
subadult birds. As in the majority of 
cases all the sutural traces of this union, 
have with the growth of this heron be¬ 
come obliterated. 
Upon the palmar aspect, just below 
the superior convex margin of this troch¬ 
lear surface, at the head of the index met¬ 
acarpal, we observe projecting forwards a 
small stumpy process. 
The distal end of the carpo-metacar- 
pus in the adult Ardea he 7 r odias is almost 
entirely occupied by the two articular 
facets for index and middle digits. A 
notch divides them. In the case of the 
first, the proximal phalanx is a long bone 
(3.8 c. m.), with a posterior blade-like ex¬ 
pansion. This latter is not very broad, 
being thick, and unpierced by foramina, 
as we sometimes see it in the Gulls and 
other water birds. A long, pointed sub- 
trihedral joint succeeds this one, which in 
turn seems to have a facet upon its dis¬ 
tal extremity, either for a claw or another 
minute joint, such as we find among the 
Ducks and Geese, but in my specimen it 
is missing. The third metacarpal sup¬ 
ports a digit composed of a single sub¬ 
compressed, narrow phalanx, nearly two centimetres long. 
Taken in connection with what Nitzsch has given us upon 
Fig. 29 .—Nycticorax violaceus 
juv. .Superior view of skull. 
Same specimen as shown 111 
Figure 28. Fife size. 
