Adaptations to A Terrestrial Existence by the Robber Crab, Birgus Latro L. III. Nitrogenous Excretion

ABSTRACT Nitrogenous excretion by the terrestrial anomuran crab Birgus latro L. was examined. The main excretory product was uric acid, representing 79·5 % of total excretory nitrogen. It was eliminated as white faeces separate from undigested food material and made up 82·6% of excretory faecal nitrogen. The faeces were the principal route of nitrogenous excretion, accounting for 96·2 % of total excretion. Loss of nitrogen in the urine and as gaseous ammonia was negligible. The midgut gland had substantial activity of xanthine oxidase and was considered to be the site of production of uric acid and its point of entry into the gut.