1. The effects of animal size and of type and concentration of food particles upon the rate of faecal pellet production in Artemia have been investigated.
2. The rate of pellet production in starved animals, and the relation between the nature of ingested particles and the size and shape of the pellet, have been determined.
3. Chitinous membranes enclose the pellets. The origin of these membranes from the gut wall has been studied.
4. The possible function of these membranes in relation to the passage of food through the gut is discussed.