G. capillastericola has an oblong, transparent, conical shell ending in a body whorl. It has a small operculum with a large proboscis. They have hermaphroditic reproductive systems. Due to their transparent shells, their soft flesh is visually exposed, demonstrating their characteristic white-and-brown striped patterning.[1][3]
As veliger, they possess a well-developed head and a foot, and small velar lobes (fleshy modules extending from the velum).[1]
^ abcdeMinichev, Yu S. (1970). "A new parasitic mollusk, Mucronalia capillastericola n.sp., living on crinoids". Issledovania po evolyutsionnoy morfologii bespozvonocnykh [= Research on evolutionary morphology of invertebrates]: 77–113.