782 



REPRODUCTIVE ORGANS 



REPRODUCTIVE ORGANS, or those which serve for pro- 

 pagation, consist of the germ-producing glands and their efferent 

 ducts, and are best considered according to sex. 



I. In the Female, a pair of Ovaries are developed, but with rare 

 exceptions only that on the left side becomes functional. The 

 mass of embryonic eggs (see page 195) of which each is composed 

 presents the appearance of a cluster of grapes, situated at the 

 anterior end of the KIDNEY of the same side, immediately below 

 the posterior end of the LIVER, and is separated from its fellow by 

 the descending AORTA, whence it receives its supply of blood, 



FIG. 2. 



REPRODUCTIVE ORGANS OF PIGEON. 



Fig. 1. Female. cZ 2 , second cloacal chamber in urodseum ; cis, inmost chamber ; k, kidney ; 

 l.od, left oviduct; lod', opening of the same into the urodseum ; l.od", infundibulum ; 

 l.od'", opening of the same into the body cavity; ov, ovary; r.od, abortive right oviduct ; 

 ur, ureter ; ur', opening of the same into the urodseum. (About 2/3 of the natural size. 

 After T. J. Parker.) 



Fig. 2. Male. 1, 2, 3, the three principal lobes of the kidney ; Ep, epididymis ; SR, suprarenal 

 bodies ; T, testes ; u, ureter ; v, vena cava posterior ; v.d, vas deferens with a swelling at 5. 

 (Natural size.) 



while it discharges into the posterior vena cava. The number of 

 germs which form the ovary frequently amounts to several hundred, 

 which during the breeding-season exhibit all stages of development 

 from a mere microscopic object to a full-grown ripe ovum, with its 

 large amount of yolk. The germs which do not ripen during the 

 season undergo a process of resorption, and this is accompanied by 

 the dwindling in size of the whole ovary, so that during winter the 

 determination of the sex of any particular bird may be a doubtful 



