GENEKATIVE OKGANS. 



319 



for instance, the left ovary only is completely developed and 

 functional. 



In Reptiles the ovaries lie near the vertebral column, and are 

 covered by peritoneum ; their lumen is penetrated by a highly vas- 

 cular network of trabeculae, enclosing the ova. In the lymph- 

 cavities thus formed the formation of ovarian follicles takes place. 

 The development of follicles occurs throughout life in Reptiles, as 



FIG. 250. MALE UBIXOGEXITAL ORGAXS OF Anguis fragilia. 

 F. Leydig.) 



(After 



Ho, testis ; f, the so-called "yellow body" (suprarenal); Ep, parorchis ; Vd, vas 

 deferens ; p, p, common aperture of the ureter (Ur, Ur l ) and vas deferens on a 

 papilla on the dorsal wall of the cloaca (Cl) ; B, urinary bladder ; r, rectum ; 

 A 7 , kidney ; ing, rudiment of the Mullerian duct. 



in the Anamnia, while in other Amniota it takes place only in 

 the embryo, or at any rate for only a short time after birth. 



The oviducts (Fig. 249, Od, Of) possess wide funnel-shaped 

 abdominal apertures, and are usually much folded transversely ; 

 their walls are provided with numerous muscular elements and 

 glands for the formation of the albumen and egg-shell. They 

 increase in size in the breeding-season. In Birds they are con- 

 siderably coiled. 



