Further additions to the British records of acephaline gregarines of earthworms

Abstract

Five species of acephaline gregarine parasites – Apolocystis pilosa Meier from Lumbricus castaneus, L. festivus, L. rubellus and L. terrestris, Monocystis arcuata Boldt from L. castaneus, Nematocystis gracilis Berlin (= N. anguillula var. gracilis) from L. castaneus and L. rubellus, Zygocystis cometa Stein from Allolobophora caliginosa and Z. eiseniae Loubatieres from Eisenia foetida – identified during the present work are new to the British record.The characteristics of two other monocystids, N. lumbricoides Hesse and N. lumbricoides var. pilosa Meier are identical apart from the presence of short ectoplasmic hairs on the latter trophozoite's body. Since the presence of ectoplasmic hairs which are projections on the trophozoite's body is often utilized in gregarine speciation, the hairy and the hairless monocystids should be described separately.Berlin (1924) identified N. anguillula var. gracilis from the seminal vesicles of Lumbricus terrestris, L. rubellus and L. castaneus. This trophozoite should have been described as a separate species, N. gracilis Berlin and not as a variety of a totally different species originally described by Hesse (1909) from a host, Pheretima rodericensis, a megascolecid oligochaete, not found in Europe.The writer wishes to express his sincere appreciation to Dr Anne Terry for her advice and useful suggestions, and to Mr D. Etherington, the head of department, for his encouragements throughout this research period.