Electron microscopic studies of the corpuscles of Stannius of an airbreathing teleost (Heteropneustes fossilis).

The ultrastructure of the corpuscles of Stannius (CS) of Heteropneustes fossilis reveals a homogenous cellular composition characterized by only one cell type, with large secretory granules and abundant ribosomal endoplasmic reticulum. These cells are comparable to the type 1 cell described in the CS of other teleosts; type 2 cells, whose presence is ubiquitous in the CS of freshwater species are absent in H. fossilis. Our data on the CS of H. fossilis demonstrate that not all freshwater species possess type 2 cells in their CS and these are not essential for life in freshwater