Habitat.—Mediterranean (Messina), surface.
Subgenus 2. Staurolithium, Haeckel, 1862, Monogr. d. Radiol., p. 401.
Definition.—All twenty spines in the centre melted and grown together, forming one single, star-like piece of acanthin.
8. Acanthostaurus cruciatus, Haeckel.
Staurolithium cruciatum, Haeckel, 1862, Monogr. d. Radiol., p. 401, Taf. xx. fig. 6.
Astrolithium cruciatum, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 811.
Spines cylindrical, of equal breadth throughout their whole length. Apex simple conical. Four equatorial spines twice as long and broad as the sixteen other spines. All twenty spines in the centre melted and grown together, forming a single piece of acanthin. Central capsule spherical, red-brown, opaque.
Dimensions.—Length of the four equatorial spines 0.12, breadth 0.006; length of the sixteen smaller spines 0.06, breadth 0.003.
Habitat.—Mediterranean (Messina), surface.