Dimensions.—Diameter of the shell 0.16, aspinal pores 0.03, sutural pores 0.01.
Habitat.—Central Pacific, Station 271, surface
Genus 353. Orophaspis,[[393]] Haeckel, 1881, Prodromus, p. 468.
Definition.—Dorataspida with twenty plates, which are perforated by forty aspinal pores (two pores in each plate). Surface of the shell without combs, dimples, and by-spines. Each radial spine bears outside of the shell two opposite free apophyses, which are either simple or branched.
The genus Orophaspis differs not only from its ancestral form, Dorataspis, but from all other Dorataspida in the development of peculiar free apophyses on the radial spines, outside the shell. These apophyses, two being opposite on each spine, appear as a repetition of the primary apophyses of Phractaspis; they are either simple or branched, and sometimes the branches are united together, forming an outer free shield with two or four pores. These outer plates represent the beginning of a second outer shell and form the transition to Phractopelta, the ancestral form of the Phractopeltida.
Subgenus 1. Orophasparium, Haeckel.
Definition.—Free apophyses of the radial spines simple, not branched.
1. Orophaspis astrolonche, n. sp.
Parmal pores of the shell circular, twice as large as the sutural pores and as the breadth of the bars. Radial spines very long, three to six times as long as the diameter of the shell, compressed, two-edged; each with two simple, opposite, triangular apophyses; their distance from the shell equal to its diameter.
Dimensions.—Diameter of the shell 0.05, parmal pores 0.004, sutural pores 0.002.