Abstract
The morphology and infraciliature of a poorly known endocommensal ciliate, Strombidium rapulum (Yagiu, 1933) Kahl, 1934, isolated from the intestine of the sea urchin Hemicentrotus pulcherrimus Agassiz, was investigated based on observations of specimens from living cells and fixed protargol impregnated cells. An improved diagnosis is given based on previous and current studies: large sized marine Strombidium in vivo 50–130 × 25–65 µm; dorsoventrally slightly flattened; outline ovate and turnip-shaped, tapering posteriorly and terminating in an elongate tail; apical protrusion about 5 µm long in live cells; one elongated macronucleus; girdle kinety equatorial composed of about 57 monokinetids; ventral kinety located subcaudally on right margin, composed of about 5 dikinetids; on average 16 anterior and 29 ventral membranelles.References
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