The preparation of centipedes for microscopical examination with particular reference to the Geophilomorpha

Abstract

Traditional methods of clearing and mounting geophilomorph centipedes have proved to be unsatisfactory. Both 60 per cent lactic acid and lactophenol, which are often used for temporary mounts, do not clear specimens adequately and cause slight swelling of the appendages, altering their shape. In addition, lactophenol contains glycerol which is hygroscopic and therefore takes up some water from the air, which is an additional disadvantage. Many workers, for example Attems and Verhoeff, made permanent mounts, macerating specimens by heating them in 10 per cent potassium hydroxide, washing, then dehydrating in a series of alcohols. They were cleared in xylene and mounted in Canada balsam. Potassium hydroxide, however, damages poorly sclerotized structures as well as the internal organs which are important for classification (for example the structure of the coxal organs) and also for assessing the maturity of the specimen (presence of spermatozoa in the seminiferous tubules of males and spermathecae of females). In addition specimens treated with potassium hydroxide become deformed under the pressure of the cover glass when mounted.