EXCRETION OF AMMONIA AND UREA IN 7 SPECIES OF MARINE PROSOBRANCH SNAILS

1. 1. None of the snails excrete urea. 2. 2. All of the snails excrete ammonia, but the degree of ammonia excretion cannot be correlated with habitat or phylogeny. 3. 3. It is suggested that the excretion of ammonia and uric acid by snails is primitive, and that an individual snail can switch from excreting predominantly one to excreting predominantly the other. 4. 4. It is suggested that uric acid can be mobile and may serve as a nitrogen depot in snails. © 1968.