Subfamily Caryostylida, Haeckel, 1881, Prodromus, pp. 449, 454

Definition.—Stylosphærida with five or more concentric, spherical lattice-shells.

Genus 56. Caryostylus, Haeckel, 1881, Prodromus, p. 454.

Definition.—Stylosphærida with five to six or more concentric lattice-shells and two free opposite spines of equal size and similar form.

The genus Caryostylus differs from its ancestral form, Stylocromyum, by the multiplication of the concentric spheres, the number of which amounts to five or six or more. I have only observed one single species of this genus. Some similar forms which in my Prodromus (1881, p. 454) were annexed to it, and disposed in three nearly allied genera (Caryoxiphus, Caryodoras, Caryolonche), have now been proved to belong to other groups, mainly ellipsoidal Druppulida.

1. Caryostylus hexalepas, n. sp.

Surface of the spherical shell smooth. Radial proportion of the component six concentric shells = 1 : 2 : 7 : 9 : 12 : 15. Both medullary shells connected only by six radial beams, opposite in pairs in the three dimensive axes. Between second and third shell numerous (twenty regularly disposed?) radial beams. Four cortical shells connected by very numerous (sixty to eighty or more?) short radial beams. Pores of all six shells regular, circular, the size increasing towards the surface, two to three times as broad as the bars. Two opposite polar spines very large, of equal size, three times as long as the shell radius, cylindrical, club-shaped at the thicker distal end. (The whole shell structure is similar to Pl. , fig. 2, but the shells are spherical, not ellipsoidal.)

Dimensions.—Diameter of the six spheres—(A) 0.02, (B) 0.04, (C) 0.15, (D) 0.18, (E) 0.24, (F) 0.3; length of the spines 0.5.

Habitat.—West Tropical Pacific, Station 225, depth 4475 fathoms.