18983) - GULAR POUCH OF THE GREAT BUSTARD 317 
Degland; but... is a separate and distinct, though delicate 
bladder. . . . After describing the very extraordinary evolutions of 
this bird during periods of display, and the great inflation of the neck 
with which they are accompanied, he goes to remark that “ All these 
facts would certainly seem to favour the idea that the pouch is 
intended to contain air, and that by the action of the muscular tissue 
. covering it conjointly with that of the sphincter at the mouth, the 
Bustard may thereby be assisted . . . in producing the peculiar 
sound (resembling ‘ ook’), which is only to be heard during the time 
when the pouch is most developed. . . .” 
Fic, 1.—The display of the Great Bustard, Otis tarda (after Wolf ), 
From Newton’s ‘ Dict. of Birds.” 
These two preparations afterwards came into the possession of 
the Royal College of Surgeons, and were described by Sir William 
Flower (6). The larger of the two sacs when empty measured 
nine inches in length, and when moderately distended with water 
was found to hold three imperial pints. 
“Both of the sacks,’ he writes, “had within them a few short 
pieces of grass and leaves. There appears to be no glandular struc- 
tures connected with the walls; indeed, the whole character of the 
sack points to its being a simple reservoir, probably for fluid, more 
analogous to the submandibular pouch of the Pelican than to anything 
else in the class Aves. But in the absence of fuller information as 
to the economy and habits of the bird, I refrain from speculating 
upon the purpose of this singular and apparently inconstant organ.” 
With Dr Cullen’s investigations and their confirmation by Pro- 
fessor Flower the existence of a pouch at least in some individuals 
was placed beyond cavil. 
