6 4 8 



BIRDS. 



The ovary is covered with follicles containing ova at 

 various stages of ripeness. As these ova become dilated 

 with yolk and otherwise mature, they burst from the ovary, 

 and are caught by the dilated end of the oviduct which 

 opens into the ccelom. The first part of the duct is narrow, 

 and there the ova may be fertilised ; the second part is 



o.v 



US. 



FIG. 322. Female urogenital 

 organs of pigeon. 



A*., Kidney with three lobes ; ., ureter ; 

 c/., cloaca; ov. , ovary; ad., oviduct; 

 f.t., funnel at end of oviduct ; r.r.od., 

 rudimentary right oviduct. 



FIG. 323. Male urogenital 

 organs of pigeon. 



T., tester; V., base of inferior vena 

 cava ; S.R., suprarenal bodies; K., 

 kidneys with three lobes (i, 2, 3) ; 

 it., ureter; v.d., vas deferens ; vs., 

 seminal vesicle ; cL, cloaca. 



wide and glandular, secreting the white of egg; in the 

 third region, which is muscular and glandular, the shell 

 membrane and shell are made. 



In sexual union the cloaca of the male is closely apposed 

 to that of the female ; only in a few cases (in ducks and 

 geese, and in the Ratitse) is there a copulatory organ. 

 The eggs are incubated by the parents for a fortnight, a 



