3. Echinaspis echinoides, n. sp. (Pl. [137], figs. 7,8).
Radial spines roundish, in the outer half conical, and two to three times as broad as in the inner half. Four apophyses of each spine doubly forked or dichotomously (more or less irregularly) branched; each spine with sixteen to twenty-four sutural condyles. Meshes of the shell four to eight times as broad as the bars. Each condyle bears a zigzag by-spine, one-third as long as the radius.
Dimensions.—Diameter of the shell 0.15; breadth of the spines 0.004 to 0.01, of the bars 0.002.
Habitat.—Central Pacific, Station 266, surface.
Genus 360. Zonaspis,[[400]] n. gen.
Definition.—Dorataspida with four plates, each of which is perforated by four crossed aspinal pores; these four plates are formed by the united branches of the other spines (eight polar and eight tropical) form no lattice-plates by union. Each condyle bears a by-spine.
The genus Zonaspis differs from all other Dorataspida in the peculiar formation of the four equatorial spines, which form by union of the recurved branches of their apophyses four perforated plates (each with four crossed pores), whilst the branches of the sixteen other plates do not unite to form plates, but simply meet the branches of the neighboring spines.
1. Zonaspis fragilis, n. sp.
Radial spines very thin and long, cylindrical. Four meshes of each equatorial plate pentagonal, ten to twelve times as broad as the bars. By-spines zig-zag, nearly as long as the radius.
Dimensions.—Diameter of the shell 0.16, of the parmal pores 0.018.