Genus 106. Cromyodrymus,[[143]] Haeckel, 1881, Prodromus, p. 454.
Definition.—Astrosphærida with four concentric lattice-spheres and numerous branched radial spines.
The genus Cromyodrymus differs from its ancestral form, Cromyomma, in the ramification of the radial spines, and exhibits therefore the same relation to it that Pityomma among the Actinommida bears to Actinomma.
1. Cromyodrymus quadricuspis, n. sp. (Pl. [30], figs. 7, 7a).
Radial proportion of the four shells = 1 : 3 : 6 : 12. All four shells with regular, circular pores, about twice as broad as the bars. Radial proportion of the pores in the four shells = 2 : 4 : 2 : 1. Radial spines fifty to sixty, three-sided prismatic, half as long as the radius, with three recurved teeth, each spine in this way bearing four points.
Dimensions.—Diameter of the four shells—(A) 0.16, (B) 0.08, (C) 0.04, (D) 0.013; length of the spines 0.03 to 0.04, breadth 0.007.
Habitat.—Central Pacific, Station 272, depth 2600 fathoms.
2. Cromyodrymus abietinus, n. sp. (Pl. [30], fig. 6).
Radial proportion of the four shells = 1 : 2 : 5 : 11. All four shells with irregular, roundish pores, twice to four times as broad as the bars. Radial proportion of the pores in the four shells = 9 : 3 : 2 : 1. Radial spines eighty to one hundred and twenty, about as long as the radius, branched like a pine tree, with six to twelve ramified branches.
Dimensions.—Diameter of the four shells—(A) 0.22, (B) 0.1, (C) 0.04, (D) 0.02; length of the spines 0.12, breadth 0.006.