FORAMINIFER

[for.a.min.i.fer] n (ca. 1842): any of an order (Foraminifera) of large chiefly marine rhizopod protozoans usu. having calcareous shells that often are perforated with minute holes for protrusion of slender pseudopodia and form the bulk of chalk and nummulitic limestone -- fo.ra.mi.nif.er.al adj