GENERATIVE ORGANS. 



321 



nearest to the Monotremes, must now be described in greater 

 detail. 



A dilated portion of each oviduct (Fig. 252, A, Od\ giving rise 

 to a uterus (Ut\ is plainly distinguishable from the rest, and its 



J> 



FIG. 251. A, MALE URINOGENITAL ORGANS OF Ornithorhynchw paradoxiis ; 



B, FEMALE URINOGENITAL ORGANS OF Echidna hystrix. 



A T , 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 Cl l ; m to m 3 , muscles of the cloaca and pen is ; 

 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 



