The mechanism of the ejection of a frothy fluid from the cloaca in the male turkey.

The mechanism of the ejection of a frothy fluid from the "tissue at the vicinity of the papilla" (TVP) of the ductus deferens and triangular fold (TF) of the cloaca of the male turkey during natural copulation was investigated. Injection of Evans blue (T-1824) solution into the wing vein of the intact male led to the ejection, immediately after injection, of frothy fluid colored blue. Ligation of the A. pudenda interna decreased the volume of fluid to a negligible amount, and removal of the paracloacal vascular body (Corpus vasculare paracloacale) completely suppressed the tumescence of the copulatory organ and the flow of the fluid (lymph-like fluid). Evans blue solution, introduced into the A. pudenda interna of dissected cloacal specimens, exuded out from the TVP but not from the lymphatic folds (plicae lymphaticae). Injection of dye solution into the paracloacal vascular body elicited only the erection of the phallus, and none flowed out from the surface of the lymphatic folds. Also, no ejection of the injected dye solution into the A. pudenda interna was found in the dorsal wall of the cloaca, particularly from the TF. The results suggest that lymph generated in the paracloacal vascular body caused only the tumescence of the copulatory organ and a lymph generated in the TVP exuded through the surface epithelium. In addition, a foam (froth) is produced in the TF of the middorsal proctodeum during mounting behavior which appears to be added to the aforementioned lymph from the TVP at copulation.