Description: Body ellipsoidal, 40 to 50 microns long, 25 to 35 microns wide, with a solid "Y"-shaped horn on the distal surface having one to four stalks, circular to quadrangular in cross section, and with an elongate aperture on the proximal surface extending nearly the full length of the body. Curvature of proximal and distal surfaces in lateral view approximately the same. Body encircled equatorially by a narrow zona, which may be a more or less indistinct structure connected to the body by exinous strips, or a more sharply delimited structure set off from the body but connected to it by a continuous, exinous band slightly thinner than the outer part of the zona. Zona of nearly uniform width, 3 to 5 microns wide, 5 to 6 microns thick near its margin. Body wall from 1 to about 1.5 microns thick on the distal and equatorial surfaces and up to 2 microns thick on the proximal surface. Body wall, zona and horn with a thin, smooth, superficial layer and a granular to vermiculate core, but not as two distinct and separable wall layers. Over-all size: length, 49 to 64 microns; height, 53 to 64 microns.