XII 



PHYLUM CHORDATA 



425 



FK 



which they are attached by folds of peritoneum. From the 



inner edge of each pass a number of delicate vasa efferentia 



which enter the kidney and become 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 



opens by numerous small 



ducts into the outer side HO 



of the ureter. Attached to 



the testis are lobed bodies 



of a bright yellow colour, 



\^Q fat-bodies (FK). 



The ovaries (Fig. 241, 

 Ov.) are large folded sacs 

 on the surface of which the 

 black and white ova pro- 

 ject. A fat-body is attached 

 to each . The oviducts ( Od. ) 

 are greatly convoluted 

 tubes, the narrow anterior 

 ends of which open into FIG. 24 o.-Rana esculenta. Urinogenital 



|-h<=> rrv>lnmp hv Qmnll an<=>r organs of the male. Ao. dorsal aorta; 



me ccelome Dy small aper. CL cloaca . Cv postcaval vein . FK _ fat 

 tures (Of.) placed close to ^^ u ; in dSST ; i 

 the bases of the lungs. -^ fe,.f^ m '' C "" 

 Their 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 ccelomic 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 



