ABSTRACT: Five different myxozoan actinosporean spore forms of 4 collective groups are described from oligochaete worms obtained from the sediments of a Scottish salmon hatchery where Sphaerospora truttae infections recur annually. Synactinomyxon 'A', synactinomyxon 'B', raabeia, triactinomyxon and aurantiactinomyxon stages are illustrated, characterised and the stimuli for their polar filament release investigated. Each actinosporean is compared with actinosporean 'species' described in the literature and actinosporean stages described from reports of 2 host myxozoan life cycles. Three of the forms reported appear to be previously undescribed.

KEY WORDS: Actinosporean · Myxosporean · Myxozoan · Sphaerospora spp.

Published in DAO Vol. 30, No. 2 (1997) on August 28
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1997