Embryonic development of the turkey male genitalia

Embryonic development of male turkey genitalia was examined to define more clearly the origin of the structures comprising the Phallus nonprotrudens. At Day 7 of incubation, the knob-like genital (g.) eminence became evident just cranial to the tail fold. A raised caudal extension of the g. eminence, the g. crest, joined the tail fold medial to the paired g. swellings. Between Days 8 and 12 of incubation, the g. eminence differentiated into the g. tubercle (which by Day 18 formed the Phallus nonprotrudens), and the g. crest formed the ventral floor of the proctodeum. By Days 10 to 11 of incubation, the g. swellings had become confluent with the lateral extensions originating from the base of the g. tubercule forming both a collar-like structure around the vent and the dorsal wall of the proctodeum. By Day 23 of incubation, the urodeum and proctodeum had become patent and the overall anatomy of the genitalia resembled that of an immature male poult.