Abstract
SEM studies on the cloacal opening of Oesophagostomum columbianum indicate that it is located on a raised conical structure called the “genital cone”. The genital cone is provided with a ventral lip and a pair of subdorsal gential appendages. The vental lip is a triangular structure having a single papilla on it and the genital appendages are covered with wrinkled cuticle with a nerve process projecting to the exterior in center. The bursa is supported by muscular rays which end up as knob-like sessile genital papillae. The inner surface of the bursa is porous. Spicules are two, equal, each provided with an ala which decreases in height distally and end up much prior to the spicular tip.