Pyrophosphate and Ethylenediaminetetraacetate as Relaxants for Lower Invertebrates Prior to Fixation

The method is based on the use of substances that can stop muscular contraction, such as chelants of calcium (EDTA) or known plasticizer of muscle (such as Na₄P₂O₇). Saturated aqueous Na₄P₂O₇ solution and 0.01 M EDTA were used at a room temperature of 22 C. A standard time of 3 hr was required for the substance to have full effect. The method was successfully tested on bdelloid rotifers and subsequently on rotifers other than bdelloid, gastrotrichs, tardigrades, amoebae and vorticellids.