Erection apparatus of the copulatory organ of ganders and drakes.
D000818:Animals; D002988:Cloaca / Q000033:anatomy & histology; D003307:Copulation; D004372:Ducks / Q000033:anatomy & histology*; D005777:Geese / Q000033:anatomy & histology*; D005837:Genitalia, Male / Q000033:anatomy & histology*; D008297:Male; D010413:Penis / Q000033:anatomy & histology