THE CLOACA IN BIRDS 189 
Fleischmann (’02).6 Recently Stieda’s point of view has been 
revived again, this time by Jolly (15), who has made it a basis 
for the theory that the bursa represents a recrudescence of the 
cloacal end of the ruptured caudal intestine. 
“The first anlage of the bursa,” he writes in his conclusion,” 
occupies exactly the situation of the post-anal intestine and it is 
orientated like it; it may be said, even, that the anlage blends 
with what remains of the post-anal intestine. One may consider 
that the bursa represents the remainder of the caudal intestine 
which rises up again posteriorly and, turned toward the head, 
undergoes a further development under the form of a true cloacal 
caecum, in the walls of which lymphoid tissue develops.”’ 
In refutation of this.theory, new evidence, presented in the 
first section of this paper, shows that the entire region of junction 
between caudal intestine and cloaca, together with the adjacent 
wall of the latter, has been removed by the process which forms 
the cloacal fenestra. There is, therefore, nothing left of this 
end of the caudal intestine which Jolly assumes to be present 
and which he describes as growing out, in an unusual direction, 
to form the bursa. Furthermore, even after the closure of the 
fenestra, the bursa does not arise at the site of the former caudal 
intestine, but on the anal side of it, beyond diverticulum a (figs. 
25 to 33). 
Another theory, presented during the last ten years, is that of 
Osawa (711), who has revived the hypothesis of Martin St. Ange 
(56). He believes that the bursa is homologous with the pros- 
tate gland even though the latter is well developed in the male 
only. Osawa bases his conclusions on the ground that the “‘ bursa 
occupies the place where the ureter and ductus deferens dis- 
charge themselves, and its follicles are laid out after the manner 
of glands.” In refutation of this view, it may be stated that the 
§ In a foot-note to his paper (p. 58) Fleischmann suggests that ‘‘the caudal 
process of the primitive urodaeum of mammals, which now bears the perplexing 
name caudal intestine, is comparable morphogenetically with the bursa of Fabri- 
cius.”’ This conjecture has recently called forth the following rejoinder from 
Keibel (’21): ‘‘The caudal intestine of birds has not the slightest thing to do 
with the bursa of Fabricius.”’ 
