Some aspects of ionic regulation in the tadpole shrimp Triops longicaudatus

Abstract

1. 1. In deionized water and in the presence of a natural food source Trips longicaudatus rapidly lost hemolymph sodium and chloride, whereas calcium and magnesium remained little changed. Mean and maximum survival times were 10·2 adn 15 hr, respectively. In natural pond water hemolymph sodium and chloride were maintained agaist a high concentration gradient. 2. 2. These results on the American species, T. longicaudatus, are distinctly dissimilar to those obtained by Parry (1961) on the Eurasian species, T. cancriformis. Apparently these two species of Triops depend on different ionic regulatory mechanisms to maintain their hyperosmoticity.