Methods are described whereby Sagitta hispida Conant was collected, induced to spawn, and the resulting larvae raised to maturity. Selection of food by size increased with age, although the larvae ingested food larger in size relative to their head width

A technique is described whereby the digestive efficiency of a plankton carnivore, Sagitta hispida Conant, which tends to feed infrequently on relatively large food organisms, was determined gravimetrically. The mean digestive efficiency in 24 experiments

The passage of food through the gut of Sagitta hispida Conant is described as a batch process and the formation of membranes which surround the faecal material is demonstrated photographically. The utility of such a peritrophic membrane system is considered