478 



COMPARATIVE ANATOMY 



Didelphys, that seen in other Marsupials may be derived. In 

 Phalangista vulpina and Phascolomys wombat (Fig. 360, B and c) 



FIG. 359. A, DIAGRAMMATIC MEDIAN SECTION TO SHOW THE RELATIONS OF 

 THE BLADDER, URINOGENITAL CANAL, AND CLOACA IN BOTH SEXES OF 

 Echidna aculeata; B, DIAGRAM OF THE ANTERIOR PART OF THE URINO- 

 GENITAL SINUS FROM THE DORSAL SIDE. (After F. Keibel. ) 



C. Dr, aperture of Cowper's glands into the urinogenital canal ; D, rectum ; Dr, 

 apertures from which project bundles of hair, with sebaceous and sweat 

 glands ; g, T, genital pouch ; K, bend in urethral canal ; L, lymphatic 

 tissue ; Mg, Miillerian duct ; PT, preputial pouch and copulatory organ ; 

 S.fi, canal of copulatory organ ; S.uy, urinogenital canal; U, ureter; U.P, 

 papilla of ureter ; Wg, Wolffian duct ; x, aperture of preputial pouch into 

 cloaca ; Z, aperture of rectum into cloaca. 



the anterior ends of the knee-shaped bends of the vaginae lie 

 closer together, and begin to extend backwards towards the urino- 



