Page 473. 
244 ON THE AUSTRALIAN BUSTARD. 
must be a sublingual pouch. It is quite possible that two effects, 
very similar in appearance, in closely allied birds, may be the result 
of different mechanisms. In the feet of the Cuculide and the Picide 
the scansorial arrangement of the toes is the result of entirely different 
dispositions of the tendons which move them; and in Otis tarda and 
Eupodotis australis the same reasoning holds. 
In both these birds there is, during the show-off, a distention with 
air of a well differentiated bag, which is in both cases lined with a 
true mucous membrane. But in Otis tarda this sac is a special struc- 
ture in front of the windpipe, opening under the tongue; whilst in 
Eupodotis australis (in the specimen under consideration at least), it 
is simply a highly dilated cesophagus. 
_ Through the kindness of Lord Lilford I am in the possession of an 
excellent Spanish specimen of the gular pouch of Otis tarda (see 
fig. 1, p. 243), with the whole of the cesophagus, the tongue, and part- 
of the trachea attached. In it the gular pouch, opening sublingually, 
is capacious, and, when distended, egg-shaped with no constriction in 
any part. The csophagus is uniformly cylindrical for its upper 
two thirds, and not at all enlarged. Lower down there is a well- 
developed globular crop. 
In the specimen of Hupodotis australis which died on May 11, as 
previously mentioned, there is no trace of a gular pouch. The eso- 
phagus is enormously dilated from its commencement (see fig. 2, 
p- 243), and gives no indication whatever of any division into tube 
and crop. Its greatest cireumference, when fairly inflated, is 14 inches, 
and the length of the distended portion of the tube is 174 inches. 
Before dissection, by filling its cavity with air, the lower portion of 
the dilated cesophagus protruded downwards considerably in front of 
the symphysis furcule, and formed the depending portion of the sac 
which was so conspicuous in the living animal. The trachea de- 
scended in front of this sac ; and when the latter was undistended, the 
former, on account of the diminished distance between the points it 
had to reach, was zigzagged from side to side in the part opposite the 
pendant portion. The keeper, J. Church, tells me that, when handling 
the sac in the living bird, he always felt a hard cord running down in 
front of it, which was evidently the windpipe. The dilated cesophagus 
was, as might have been expected, covered with two coats of muscular 
tissue, the outer longitudinal—and the inner transverse. The mucous 
lining presented no peculiarities. The skin in front of the neck was 
lax, with a considerable amount of coarse fat in its deeper layer ; it 
was engorged with blood, tortuous vessels running through it in all 
directions. 
I may mention as an anatomical peculiarity of interest that Huwpo- 
dotis australis and EH. denhami possess but one carotid artery, the right 
