ULTRASTRUCTURE OF SENSORY ENDINGS IN DIPLOSTOMUM-PSEUDOSPATHACEUM NIEWIADOMSKA, 1984 CERCARIAE (DIGENEA, DIPLOSTOMIDAE)

Using TEM techniques, 13 types of sensory endings were revealed on the body and tail of cercariae of D. pseudospathaceumm. They differ in th e presence or absence of cilia, number of cilia, number of electron-de nse rings, basal body type and collar shape. The following groups of s ensory endings were distinguished: uniciliate with a short (5 types), moderately long (one type) or long cilium (4 types); multiciliate sens ory pits (2 types); and nonciliate sensory bulbs. Most sensory endings with long cilium and nonciliate sensory bulbs were found on the tan s tem. All the breviciliate sensory endings and multiciliate sensory pit s, as well as 1 type with long cilium, were situated on the cercarial body. The uniciliate sensory endings with a moderately long cilium wer e found on the furcae. The ultrastructuraI variety of sensory endings in different groups of Digenea, as well as their supposed functions, a re discussed. Copyright (C) 1996 Australian Society for Parasitology. Published by Elsevier Science Ltd.