THE EFFECTS OF SEX HORMONES ON THE DEVELOPMENT OF THE RIGHT GONAD IN FEMALE FOWL¹

Abstract

BIRDS, unlike other vertebrates, normally have but one functional ovary, located dorsalty on the left side of the abdomen. In the domestic fowl, the right and left embryonic gonads develop concurrently until the 7-9th day of incubation at which time there is a retardation of growth, followed b}r retrogression, of the right organ (Swift, 1915; Brode, 1928). This right rudimentary gonad persists in the adult hen as an inconspicuous, flattened ridge of tissue, closely applied to the inferior vena cava. It is reported to be composed of medullary tissue, with cortical tissue rarely present (Willier, Gallagher and Koch, 1935; Domm, 1939; Snedecor, 1949). According to Lillie (1927), cortex is found only if regression of the right gonad is delayed until after the time proliferation of cortical cords normally occurs in the left ovaiy (8–11 days of incubation). Occasionally, this organ develops into a more or less typical right ovary. Domm (1939) reported that such ovaries, ranging