A second cell type in Stannius bodies of two euryhaline telecost species.

In the corpuscles of Stannius of sticklebacks and eels two cell types are described of presumably endocrine nature. The predominating type, comparable to the cells observed in other species, responds to variation in calcium content of the medium and possibly produces a hypocalcemic hormone. The second cell type is unreactive to calcium. Since it is more active in freshwater than in seawater specimens, this cell type is possibly involved in ionic regulation. It was not found in two seawater teleost species.