GENERATIVE ORGANS. 



321 



nearest to the Monotremes, must now be described in greater 

 detail. 



A dilated portion of each oviduct (Fig. 252, A, Off), giving rise 

 to a uterus (UP), is plainly distinguishable from the rest, and its 



A 



FIG. 251. A, MALE URINOGENITAL ORGANS OF Ornithorhynchus paradoxus ; 



B, FEMALE URINOGENITAL ORGANS OF Echidna hystrix. 



N, kidneys ; Ur, ureter ; B, urinary bladder ; Sug, urinogenital sinus ; Ho, testis ; 

 Ve, vas efferens ; Ep, epididymis ; Vd, vasdeferens ; Od, oviduct ; r, rectum ; 

 Cl, cloaca, opening to the exterior at CZ 1 ; m to m 3 , muscles of the cloaca and penis ; 

 Gp, glans penis, enclosed within its fibrous tube ; Pp, prepuce ; Cli, clitoris ; 

 *, *, aperture through which the copulatory organ extends into the cloaca. 



narrowed posterior end comes into close contact with its fellow in 

 the middle line. At this point (f) each uterus is connected with 



Y 



