Haeckel, 1887
Two main vertical spicules of different shape: one directed forwards, with 2 diverging, slightly bent horns; other, directed toward back (posterior), may be spindle-, lance- or sword-shaped, and may also bear 2 diverging or parallel horns. Tropical spicules much shorter, ending in 2 small diverging horns. Polar spicules arborescent, reduced in size and number, may be rudimentary. Central capsule rhomboidal or pillow-shaped. Length of equatorial spicules: 0.4-0.8 mm.