312 MR. W. A. FORBES ON THE [Apr. 17, 
giving the whole somewhat the appearance of a shortened and clumsy 
antenna of a butterfly (see fig. 3, p. 311) It disappears completely 
in adult birds. In specimens of Dacelo gigantea, Merops, and 
Momotus lessoni it was sac-like and of considerable size. In 
the Parrots it is well marked and bag-like, opening by a small 
pore. As already mentioned, in an oid specimen of Platycercus 
icterotis I found the bursa well marked, though its opening into 
the cloaca was nearly obliterated. In a specimen of Stringops I 
found no bursa. In the Accipitres it forms a moderate-sized 
pyriform sac; in old birds this becomes reduced to a sort of 
small conical pouch in the substance of the back wall of the cloaca 
at the place of aperture. Of the Steyanopodes, in Phalacrocorax 
(2 species) and Sula bassana the bursa is a large sac, 14-2 inches 
in length, which opens by a small pore in the usual places. The 
walls of the bursa are very thick; they are traversed by about 
seven rows of large, irregular, crypt-like pores, separated by smooth, 
narrowed, raised ridges. The ridges and pores disappear towards the 
base of the bursa; but the upper part has a curious honeycomb-like 
appearance, somewhat like that of the Ruminant reticulum. The 
internal surface is covered with numerous, small, opaque, granular- 
looking corpuscles, especially towards the apex. In a young speci- 
men of Plotus anhinga (2) that I dissected, the appearance and 
disposition of the parts agreed very well with Prof. Garrod’s de- 
scription. I noticed, however, that the opening of the bursa was 
very slightly constricted by a slight fold of mucous membrane on 
each side, so that the bursa hardly opened by its entire width into 
the cloacal chamber. In other respects it showed a strong approxi- 
mation to the disposition of these parts that I shall presently describe 
in the Ostrich and its allies. 
In the Herodiones the bursa is large and sac-like, with a small or 
moderate opening ; its interior surface has no ridges or sulci, but 
large crypt-like pores collected in patches. In aged birds it seems 
to disappear, though in a specimen of Aédimia that had lived in the 
Gardens more than three years it was still present, 3 inch long, with 
the opening still unobliterated. 
In Chauna the bursa is a glandular pyriform sac, about 1 inch in 
length, with a moderate-sized opening (see fig. 1, p. 309). It seems 
to disappear entirely in old birds. In a specimen of Cygnus olor it 
was a large conical sac, 14 inch long, with a wide mouth, but slightly 
constricted off, and with no large glands. In aged specimens of 
Fuligula rufina, which had lived sixteen years in the Gardens, and of 
Tadorna rutila, which was nearly eighteen years old, the bursa had 
disappeared, in the former having assumed the appearance of a round 
cord-like ligament, in the latter having become fused with the abdo- 
minal aponeurosis. In each case a small pore marked the place of 
aperture. 
In Pterocles, Goura (in a nine-months-old bird), and Phaps I 
have never found any thing more than a small blind pore in the usual 
place of the opening; as we know from M. St.- Ange, the bursa dis- 
appears very early in Columba livia as well. 
