XIII 



PHYLUM CHORDATA 



287 



anus IS 



CvAo 



from the outer borders of the kidneys and open into the dorsal 

 wall of the cloaca {CI). The kidney is developed from the 

 mesonephros of the embryo, the ureter from the mesonephric duct. 

 In the larva a large pronephros is present and is, for a time, the 

 functional kidney. 



Opening into the cloaca on its ventral side is an organ 

 (Fig. 929, 11.) mentioned in the general account of the Craniata 

 (p. 120), but here actually met with for the first time. It is a 

 bilobed, thin-walled, and very delicate sac into which the 

 urine passes by gravitation from the cloaca when the 

 closed. The sac is a urinary 

 Madder, but, as it is quite different 

 morphologically from the organ of 

 the same name in Fishes, which is 

 a dilatation of the ureter, it is dis- 

 tinguished as the allantoic Madder. 

 . The tesies (HO) are white ovoid 

 bodies lying immediately ventral 

 to the anterior ends of the kid- 

 neys, to which they are attached 

 by folds of peritoneum. From 

 the inner edge of each pass a 

 number of delicate vas efferentia 

 which enter the kidney and be- 

 come connected with the urinary 

 tubules. • The spermatic fluid is 

 thus passed into the urinary 

 tubules and carried off by the 

 ureter, which is therefore a urino- 

 genital duct in the male Frog. A 

 vesicula seminalis (Fig. 929,vs.sem.) 

 opens by numerous small ducts 

 into the outer side of the ureter. 

 Attached to the testis are lobed 

 bodies of a bright yellow colour, 

 the fat-hodies {FIC). 



The ovaries (Fig. 938, Ov.) are 

 large folded sacs on the surface 

 of which the black-and-white ova project, 

 to each. The oviducts (Od.) are greatly 

 narrow anterior ends of which open into 

 apertures (Ot.) placed close to the bases 

 posterior ends are wide and thin-walled (Ut.), and open into the 

 cloaca (P). The ova break loose from the surface of the ovary and 

 enter the coelomic apertures of the oviducts, the walls of which are 

 glandular and secrete an albuminous fluid having the property of 

 swelling up in water. The eggs receive a coating of this substance 



Fig. 937.— Bana esculenta. Urino- 

 genital organs of the male. Ao. dorsal 

 aorta ; CL cloaca ; Cv. postcaval vein ; 

 FK, fat bodies ; BO, testes ; if, kidneys ; 

 S, apertures of ureters into cloaca ; Cr. 

 ureters. (From Wiedersheim's Com- 

 parative Ayiatomi/.) 



A fat-body is attached 

 convoluted tubes, the 

 the coelome by small 

 of the lungs. Their 



