小可能是年龄的标志，小壳是幼体，大壳则是成熟的个体(Gold and Morales, 1976b)。They were among the many planktonic microorganisms featured in Ernst's恩斯特·海克尔's classic work popularizing the beauty of the natural world "Art forms in Nature" (自然界的艺术形态).如同其他原生生物，砂壳纤毛虫属于一种复杂的单细胞真核生物。