Fig. 2

Oviducts of an infantile (A), laying (B), and 35-day brooding Muscovy duck in situ. The sternum and ventral portions of the abdominal air sac were removed. Visible structures include the left ovary (1), oviduct (2) with an egg still lacking a shell in the shell gland (2*), and the urodaeum (3) of the cloaca