258 



MR. W. P. PTCRAFT ON THE MOEPHOLO&T AND 



chamber, though this is but small and not very sharply defined. In this succession of 

 chambers therefore, as Dr. Gadow has pointed out, Strnthio resembles some Saurians 

 and young Crocodiles. 



In Strnthio, defaecation and micturition are separate acts, and the urine, instead of 

 passing from the uro- to the coprodseum, is transferred to the bursa Fairicii, which, 

 unlike that of all otlier 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 PakeognatJue, as in Neognathce, is round, not transverse 

 as in Reptilia. 



Fi?. 9. 



^'/ .. 



The terminal end of the alimentary canal of Casuarivs vioKcoUis, to show the cloaca and its divisions 

 into copro-, uro-, and iirootodaeum and the form and position of the bm-sa Fabricii. 



/)./. = buraa Fabricii. 

 c.d. = coprodjeum. 

 u.d. = urodceum. 

 p.d. = proctodeum. 



d. = clitoris. 

 ovid. = aperture of oviduct. 

 II. = aperture of ureter. 



b. The Bursa. 



The bwsa Fabricii of the Palceoynathce has been very carefully studied by Forbes 

 [20] and Wenckebach [97]. 



In the Palceognathce — save only in Apteryx — as Forbes [20 a] has shown, the 

 bursa in young birds is of considerable size. Furthermore, he held that it differed 



