poikilosmotic
/ˌpɔɪkɪlɒzˈmɒtɪk/(also poikilo-osmotic) Zoology
adjective
Of an animal: that allows the concentration of dissolved substances in its body fluids to vary with fluctuations in that of the surrounding medium. Opposed to homoiosmotic.
Origin
Early 20th century; earliest use found in The Biological Bulletin. From poikilo- + osmotic, after German poikilosmotisch.