ABSTRACT
The effluent tracts (tube[sl) of the alkaline gland sacs empty through the urinary papillae within the cloaca. The close anatomical proximity of the opening of the sac with that of the sperm duct in skates prompted Smith (1929) to speculate that the alkaline pH (8.0-9.2) of the fluid functioned to buffer the acidic pH of the urine, thus protecting the sperm during its exit into the cloaca, presumably laden with urine. However, reports of elasmobranch urine pH are rare and those that are published do not indicate that it is acidic (Choe and Evans 2003).
