OBSERVATIONS ON ULTRASTRUCTURE OF THE ANTERIOR ADHESIVE AREAS AND OTHER ANTERIOR GLANDS IN THE MONOGENEAN, MONOCOTYLE SPIREMAE (MONOCOTYLIDAE), FROM THE GILLS OF HIMANTURA FAI (DASYATIDIDAE)

Observations with the light microscope and the scanning and transmissi on electron microscopes have shown that the anterior end of Monocotyle spiremae has 8 slit-like apertures on the ventrolateral margins at ea ch side of the mouth. Gland cells located next to the pharynx produce rod-shaped secretory bodies that are conveyed in ducts that open on to the surfaces of rounded lobes inside ''reservoirs'' behind each ventr al, slit-like aperture. Rod-shaped secretary bodies are extruded into the ''reservoirs'' and appear to combine and form a homogeneous secret ion which may bond the ventrolateral regions of the head of the parasi te to a substrate. At no stage, however, were intact rods observed out side the duct endings. Gland cells that produce an ovoid secretory bod y also supply the head of M. spiremae, but ducts from these open dorsa l and anterior to the mouth in a region where the parasite is not know n to attach. There appears to be Little or no chance for the ventral r ods and the dorsal avoid secretion to mix. This is the first record of a monogenean parasite with a single type of secretion supplying the v entral surfaces of the anterior end. The rods in M. spiremae differ in some respects from the rod-shaped bodies recorded previously among gy rodactylid, dactylogyrid, capsalid and acanthocotylid monogeneans. (C) 1997 Australian Society for Parasitology. Published by Elsevier Scien ce Ltd.