Nematode Feeding Mechanisms. 1. Observations On Rhabditis and Pelodera

Abstract

Oesophageal structure of Rhabditis (Cephalohoides) oxycerca and Pelodera (Cruznema) lambdiensis was studied from sections and whole mounts and the mechanism of food intake from cine films. Water, with suspended food particles small enough to pass through the stoma, is drawn as far as the fore end of the isthmus by sudden dilation of the pro- and metacorpus. Closure of the lumen in these regions expels excess water and the accumulation of food is passed steadily backward by a wave of contraction of the radial muscles of the isthmus. Particles are drawn between the bulb flaps by dilation of the haustrulum and are passed to the intestine by closure of the haustrulum and by dilation, followed by closure of the oesophago-intestinal canal. The bulb flaps may contribute to the closure of the inlet valve to the haustrulum, but they also compress food particles when they invert and some particles are thus ruptured.