Bacterial strains isolated from the kidney and liver of grey mullets, Mugil platanus Giinther, 1880, captured in Cananéia, São Paulo State, Brazil, in October 1996, belong to the genera Micrococcus, Pseudomonas, Flavobacterium, Aeromonas and Vibrio. The resistance/susceptibility patterns of the isolated micro-organisms to nine antimicrobial substances were determined, the more resistant bacteria had been Pseudomonas, Flavobacterium and Micrococcus. To the best of the authors knowledge this is the first bacteriological study done on Mugil platanus in Brazil.

The Stannius corpuscles of Prochilodus scrofa are studied microscopically (both optically and electronically) as well as macroscopically. Two CS, and sometimes 3 or 4, are found per animal. They are pink-coloured organs, rounded in shape and scattered laterally in the first anterior third of the kidney. Each CS is enveloped by a thick connective tissue capsule. The grandular parenchyma consists of only one cellular (PAS-/AF-) type, cylindrical in shape, with oval or rounded nucleus located eccentrically with visible nucleolus. The ultrastructural description is as follows: well developed Golgi complexes, rough endoplasmic reticulum and mitochondria in moderate quantities. Electron-dense granules numerous. CS highly vascularized.