Excretion of Hypertonic Urine by a Teleost.

During the course of adaptation to sea water, Fundulus kansae excretes urine that is hypertonic to the blood, but hypotonic to sea water. During this period the osmotic pressure of the serum is greater than that found in animals adapted to fresh water or sea water. The urine collected from fish adapted to sea water is usually isotonkc to the blood. route, presumably the gills.