Springer Online Journal Archives 1860-2000
Abstract The surface topography of three cestode parasites from the gut ofSqualus acanthias is described with the aid of scanning electron microscopy (SEM). The cestodes areTrilocularia acanthiaevulgaris, which occurs in both stomach and spiral valve, andPhyllobothrium squali andGilquinia squali, which only appear in the latter. Differences between the stomach and spiral valve forms ofT. acanthiaevulgaris are recorded. The anterior third of the free proglottis of this species is covered by numerous large, backwardly-projecting spines. Bands of similar, though smaller, spines encircle the anterior margins of proglottides still attached to the strobila and grow larger as the proglottides mature. The adherent surface of the bothridia ofP. squali is covered by large numbers of minute “ear-of-corn” projections, in addition to more normal microtriches, whilst that ofG. squali bears numerous flat, plamate structures. The mature and free proglottides ofG. squali possess large numbers of short, rod-like structures around the genital pore and they are surrounded by a ring of hummock-like papillae. The possibilities of these microtopographical features being used in a sensory and/or attachment role are considered. The value of SEM as a taxonomic aid in cestode systematics is briefly discussed.
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