Anal and Oral Water Intake by Crustacea

Abstract

IN the majority of small and transparent Crustacea, water can be seen with a microscope to be pumped into the alimentary canal by rhythmic antiperistaltic movements of the rectum repeated at intervals of one to a few seconds. This anal drinking is continuous in small species and in the young of larger species; it occurs in intermittent series of gulps in the adults of larger species.