Xiphacantha serrata, Haeckel, 1862, Monogr. d. Radiol., p. 386, Taf. xvii. fig. 3, Taf. xviii. figs. 14a, 14b.
Xiphacantha serrata, R. Hertwig, 1879, Organismus d. Radiol., p. 11, Taf. ii. fig. 4.
Acanthometra serrata, Haeckel, 1860, Monogr. d. Radiol., p. 807.
Spines in the distal half thin, nearly cylindrical or a little compressed, thinned towards the short simple or bifid apex; in the proximal half three to six times as broad, four-winged, with six longitudinal rows of opposite apophyses. From the edges of the two broader (lateral) wings arise three to four pairs of strong conical teeth; from the edges of the two smaller (sagittal) wings arise also three to four pairs of teeth, but very short and broad, triangular; each of these teeth bears on both its (lateral) sides two opposite slender conical teeth, which are parallel to the large conical teeth of the lateral wings. Therefore all teeth (eighteen to twenty-four) are placed opposite in pairs in three parallel planes. Base of the spines pyramidal, with a small leaf-cross. The central capsule of this large and very remarkable species commonly entirely includes the apophyses of the spines, and is opaque, whitish.
Dimensions.—Length of the spines 0.2 to 0.3, breadth of the distal half 0.002 to 0.004, of the proximal half 0.01 to 0.02.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.
Subfamily 3. Stauracanthida, Haeckel.
Definition.—Astrolonchida with a cross of four free apophyses (or four crossed longitudinal rows of apophyses) on each radial spine.
Genus 330. Xiphacantha,[[370]] Haeckel, 1862, Monogr. d. Radiol., p. 384.
Definition.—Astrolonchida with four simple apophyses on each radial spine, opposite in pairs in the form of a cross.