On the morphology and biology of a new arhynchodine thigmotrichid ciliate (Protozoa) from the dog whelk Nucella lapillus



Ancistrumina nucellae, sp. n. belongs to the family Hemispeiridae and shows characters intermediate between the genera Ancistrum and Ancistrumina. It is compared here with other Ancistrumina spp. It occurs most abundantly during the winter, particularly in Nucella about 3.5 cm long.