Effects of Methods of Killing, Fixing and Mounting On Measurements of Anguina Agrostis

Abstract

Techniques for the preparation of Anguina agrostis for morphological measurements were compared. These included killing and fixing in hot or cold phosphate buffered 4% paraformaldehyde and then either mounting in fixative or processing further before mounting in lactophenol or glycerol. All ten characters measured except the length of the stylet and the distance from the base of the stylet to the dorsal oesophageal gland orifice were reduced by both fixation methods. Subsequent processing caused further shrinkage of eight characters after hot fixation and of seven characters after cold. Five of these characters shrank more after hot than after cold fixation. Further shrinkage also occurred in specimens processed to araldite for electron microscope studies. Measurements closest to those of living nematodes were obtained from specimens cooled, whilst alive, in phosphate buffer at 5° and then fixed at this temperature in phosphate buffered 4% paraformaldehyde and subsequently mounted in this fixative without further processing.