THE URINOGENITAL ORGANS OF VERTEBRATES. 159 



(4) The united lower parts of Wolffian and Miillerian ducts 

 which are really the lower unsplit part of the segmental ducts of 

 the kidneys. 



FIG. 6. DIAGRAM OF THE URINOGENITAL ORGANS OF A MALE SALAMANDER. 

 (Copied from Ley dig's Histologie des Menschen u. der Thiere.) 



md. MUller's duct (rudimentary); y. remnant of the secretory portion of the 

 segmental duct Kopfniere ; Wd. Wolffian duct ; a less complete structure in the 

 male than in the female ; st. segmental tubes or kidney. The openings of these into 

 the body-cavity are not inserted in the figure ; t. testis. Its efferent ducts form part 

 of the kidney. 



In the female, there are (Fig. 7) 



(1) The Miillerian ducts which function as the oviducts. 



(2) The Wolffian ducts. 



(3) The kidneys. 



(4) The united Miallerian and Wolffian ducts as in the 

 male. 



Wfif 



m.d 



FIG. 7. DIAGRAM OF THE URINOGENITAL ORGANS OF A FEMALE SALAMANDER. 

 (Copied from Ley dig's Histologie des Menschen u. der Thiere) 



Md. Muller's duct or oviduct ; Wd. Wolman duct or the duct of the kidneys ; 

 st. segmental tubes or kidney. The openings of these into the body-cavity are not 

 inserted in the figure ; o. ovary. 



The urinogenital organs of the adult Amphibians agree in 

 almost all essential particulars with those of Selachians. The 



