Number, shape and size of nucleus
There are variations with respect to shape of nucleus also. It may be spherical, oval to flattened lobe or irregular in shape. In most cases it has a regular outline, but may also have irregular outline. Shape of nucleus also depends on the cell. In spheroid, cuboid or polyhedral cells, nucleus is usually spheroid. In cylindrical, prismatic or fusiform cells, nucleus is ellipsoid. Irregular nuclei are sometimes found in some neutrophylls or leukocytes and branched nuclei are sometimes found in glandular cells. In still other cases like spermatozoa, pyriform or lanceolate nuclei may be found.