Studies on the accessory reproductive organs in the drake. 1. Addition to semen on the fluid from the ejaculatory groove region.

This study was performed to clarify whether the semen from the vasa deferentia is diluted with a fluid before ejaculation and to locate the ejecting region of the fluid. Vas deferens semen, ejaculated semen and the fluid ejected from the ejaculatory groove region were obtained from the drake and their characteristics were determined. The mean concentration of ejaculated semen, 9.46 millions/mm.3, was nearly half as much as that of ampulla semen (semen contained in the dilated portion of the vasa deferentia; 20.40 millions/mm.3), and the former had positive aldose color reaction in contrast with complete negative reaction in the latter, suggesting that ampulla semen might be diluted twofold with a fluid containing aldose before ejaculation. The aldose positive fluid was observed to be ejected from the ejaculatory grove region of the cloaca and it could be collected from the vasectomized drake using an artificial vagina. Thus, the ejaculated semen of the drake, about 0.4 ml. in volume, was considered to be a mixture of the semen ejected from the vasa deferentia (estimated to be about 0.2 ml.) and the fluid ejected from the ejaculatory groove region (about 0.2 ml.). The pH value, glucose content and electrophoretic pattern of protein of the ejecting fluid were similar to that of blood plasma, and it was assumed that the fluid might be a fluid of blood origin.