1832. | ANATOMY OF AN AUSTRALIAN DUCK. 457 
the duplicature of the frenum lingue*. Ona opening the mouth, the 
tongue being forced up against the roof of the mouth as is depicted 
in fig. 2, there is seen at its base, some way behind the level of the 
basihyal, a small circular aperture, about the size of a pea, lying be- 
tween the two folds of the frenum, the left of which is much stronger 
and better developed than the right. This aperture is the mouth of 
a small pouch, almost large enough to receive the end of the little 
finger, which extends backwards for some little distance to the base 
of the tongue, its breadth being nearly as great as that of that organ. 
This pouch is lined by mucous membrane of similar character to that 
found over the adjacent parts of the mouth ; its anterior limit extends 
forwards as far as the posterior end of the curious wattle attached to 
the lower jaw; but there is no connexion between the two, the wattle 
being merely formed by a fold of the integuments, with no cavity 
contained in it. 
The observations hitherto made on the habits of Biziura in its 
native state fail to throw any light on the use or raison d étre of 
this curious structure, though, judging from analogy, it is nearly 
certain that it is in some way connected with display during sexual 
excitement, and therefore confined, as we know the wattle is, to the 
male sex. ‘The first specimen I examined had, I may remark, the 
pouch less developed than in the second one, probably an older bird. 
It is not improbable that further observations may show that, in 
thoroughly adult and breeding birds, this pouch acquires much 
greater dimensions than was the case in these two specimens. 
As regards other points, Biziura is in most of its features thoroughly 
Anatine. The tongue is quite duck-like, though very broad. There 
is a well-developed penis of the peculiar type found in other Anatidee. 
The number of remiges is 28, of which ten are, as usual, primaries. 
The pollex bears a small claw. There are 24 rectrices, a number 
not exceeded in any of the Anseres, though found in certain Swans. 
All are peculiarly stiff and curved, with flat lamellar rhachises. The 
ceca are long, measuring 6°75 and 7°75 inches respectively in the two 
Specimens. The ambiens muscle is large, and peculiar in that its 
tendon perforates the large-sized triangular patella, just as it does in 
Phalacrocorax and the extinct Hesperornis. 
The carina sterni is shallow, as might have been expected in a bird 
with such weak powers of flight as Biziura has. There is a minor 
myological peculiarity in the hind limb of Biziura, such as I have 
not yet observed in other Anserine birds. In all these the flevor 
longus hallucis and fleror profundus digitorum blend together to- 
wards the lower part of the tarso-metatarse, a comparatively very 
insignificant tendinous slip being given off from the tendon of the 
first-named muscle to the hallux before it blends with the other’. 
In Biziura the two tendons completely blend, but the small tendinous 
slip, given off, as usual, before they unite, does not go to the 
hallux as it normally does, but continues down to the bottom of the 
bone, and is there lost on one of the annular masses of fibro-cartilage 
' Murie, P. Z.S. 1869, p. 140; and Garrod, Coll. Papers, p. 245. 
2 Garrod, Coll. Papers, pp. 293 and 298, oe 
