Glands associated with the anterior adhesive areas and body margins in the skin-parasitic monogenean Entobdella soleae

Abstract

Using the light microscope and TEM, a detailed study has been made of the different kinds of gland cell opening on the body surfaces of the adult and the oncomiracidium of E. soleae. Particular attention has been paid to the gland cells supplying the anterior adhesive areas and to those gland cells opening along the margins of the head region and body of the parasite. The oncomiracidia as well as immature parasites have three adjacent adhesive sacs on each side of the head and the adhesive regions of adults and oncomiracidia are supplied with two kinds of secretion. The most abundant secretion takes the form of rod-shaped bodies which, in the oncomiracidium and in the adult, are transported through ducts with multiple apertures, each aperture usually permitting the passage of a single rod. The second secretion consists of roughly spherical vesicles which differ in appearance in oncomiracidia and adults. Most of these ducts appear to have single apertures but there is evidence in the adult that some of them branch and lead to more than one opening. The roles of these two kinds of secretion in attachment and detachment of the head region, in immature and in adult parasites, were studied experimentally. In immature and mature parasites ultrastructural studies reveal similarities between the secretory bodies produced by the anterior median head glands and those produced by gland cells opening on or near the body margins. Possible functions of the secretions of the marginal gland cells are discussed.