Presence of a Peritrophic Membrane in Diplopods

Abstract

The presence of a peritrophic membrane has been reported in the midgut of the following classes of mandibulate Arthropoda: Onycophora, Crustacea, Insecta and Chilopoda¹. It has not been reported in the Diplopoda, although Randow² stated that the brush border of the midgut epithelial cells may slough off. We have dissected tubular membranes giving a positive chitosan reaction³ from the midguts of the following British millipedes: Tachypodoiulus niger, Ophyiulus pilosus, Iulus scandinavius, Cylindroiulus punctatus (Iulidae), Glomeris marginata (Glomeridae), Polydesmus angustus (Polydesmidae), Polymicrodon polydesmoides (Craspedosomidae) and Choneiulus palmatus (Blaniulidae). The presence of a similar membrane has been inferred from paraffin sections of the midgut of Polyxenus lagurus (Polyxenidae). In none of these is there an œsophageal valve; it is therefore inferred that the peritrophic membrane arises by delamination of the brush border from the midgut epithelial cells. A delaminating brush border has been observed in O. pilosus, C. punctatus, G. marginata, P. polydesmoides and C. palmatus. Furthermore, in G. marginata, P. angustus, T. niger, I. scandinavius, C. punctatus and P. polydesmoides concentric peritrophic membranes were seen in sections, a phenomenon often observed when membranes are formed by delamination⁴.