18'<2.J ANATOMY OF AX AUSTRALIAN DUCK. 4')? 



tlie (luplicatiire of the fr(EiiHin linf;ua\ O.i opening the month, the 

 tongue being forced up against the roof of tiie mouth as is depicteJ 

 in fig. 2, there is seen at its base, some way behind tlie level of tiie 

 basihyal, a small circular aperture, about the size of a pea, lying be- 

 tween the two folds of the frcenum, the left of which is much stronger 

 and better developed than the right. Tliis aperture is tlie 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 Bizlura in its 

 native state fail to throw any light on the use or raison d'etre 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 bad, 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 pecuhar type found in other Anatidse. 

 The number of remiges is 2S, 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 

 caeca are long, measuring 6v5 and I'la 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 flexor 

 longus hallucis and flexor profundus diyitorum 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. 18G9, p. 140; and Garrod, Coll. Papers, p. 245. 

 2 Garrod, Coll. Papers, pp. 293 and 298. 



31* 



