258 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
chamber, though this is but small and not very sharply defined. In this succession of 
chambers therefore, as Dr. Gadow has pointed out, Struthio resembles some Saurians 
and young Crocodiles. 
In Struthio, defecation and micturition are separate acts, and the urine, instead of 
passing from the uro- to the coprodzum, is transferred to the bursa Fabricii, which, 
unlike that of all other birds, is of considerable size and remains permanently open. 
Its function, acting as a physiological dorsal bladder, is unique. A true allantoic 
bladder, communicating directly with the ureters, is wanting in the Aves. 
The cloacal ‘aperture of the Paleognathe, as in Neognathe, is round, not transverse 
as in Reptilia. 
Fig. 9. 
The terminal end of the alimentary canal of Casuarits violicollis, to show the cloaca and its divisions 
into copro-, uro-, and proctodseum and the form and position of the bursa Fabricii. 
bf. = bursa Fabricii. 
e.d, = coprodeum, 
u.d. = urodeeum. 
p.d. = proctodeum. 
cl. = clitoris. 
ovid. = aperture of oviduct. 
U. 
= aperture of ureter. 
6. Tue Bursa. 
The bursa Fabricti of the Palwognathe has been very carefully studied by Forbes 
[20] and Wenckebach [97]. 
In the Palewognathe—save only in Apteryw—as Forbes [20 a] has shown, the 
bursa in young birds is of considerable size, Furthermore, he held that it differed 
