NOTES ON THE FEEDING MECHANISM AND ON INTESTINAL RESPIRATION IN CHÆTOPTERUS VARIOPEDATUS

Abstract

1. The food of Chætopterus is transferred from the dorsal thoracic groove to the mouth by the temporary adaptation of the dorsal lip to form a conducting channel leading directly into the mouth from the blind anterior termination of the groove. 2. This reaction of the dorsal lip can be induced by mechanical stimulation of the anterior part of the dorsal groove. 3. Clear and colorless somites which have been regenerated recently at the hind end of a Chætopterus demonstrate the occurrence of antiperistaltic contractions in the alimentary canal of the hind segments; such individuals also show a "gulping" action at the anus, and an accessory pumping mechanism in the walls of the intestine amplifying the peristaltic contractions.