1877. ] BURSA FABRICII IN BIRDS. 313 
In the Galline the bursa has a tubular or pyriform shape, with 
numerous well-marked alternating ridges and furrows, the latter 
highly glandular, on its internal surface. These ridges are most 
marked towards the superior (blind) end, and are formed by the pro- 
jection into the interior of collections of lymphatic follicles. These 
last do not open by distinct pores into the cavity of the bursa, but 
are entirely closed, as shown by Signor Alesi and Leydig. In the 
process of atrophy the peduncle becomes solid ; also the cavity of the 
bursa becomes shut off from the cloaca, and persists in this state for 
some time. Finally, however, the bursa seems to become reduced 
to a ligament-like structure, or to become fused with the general apo- 
neurosis. In the Turkey the bursa is a long tubular sac, 2 inches 
long, with very well marked ridges and sulci. In all a pore marks 
the opening of the atrophied bursa. In Serpentarius the bursa is 
Fig. 4. 

Cloaea of Casuarius uniappendiculatus, viewed from behind. 
a, a. Out surface of posterior wall of bursa. 6. Opening of cloacal chamber 
into bursa. c¢. Pointer passing from cavity of bursa to exterior. d’. 
Pointer passed from cloaca into bursa through opening 4; the upper 
part is supposed to be seen through the wall of cloaca. e. Clitoris. 
a large globular sac, with the glandular area confined to the apical 
region and a small aperture into the cloaca. In these respects it 
resembles Otis and Grus. In Porphyrio and Ocydromus it assumes 
the form of a jong, narrow, cylindrical tube, the central cavity of 
which becomes closed up as atrophy advances. In Gidicnemus there 
is a similar form of bursa. In Aftagis, on the other hand, the form 
is pyriform, more like that of the Passeres and Galline. 
