Siphonasphis cristata, Haeckel, 1882, Manuscript.
Shell with numerous (one hundred to two hundred?) funnel-shaped dimples, each of which is pierced at the bottom by one or more pores. Twenty larger dimples in the centre of the plates are pierced by the radial main-spines; among these fourteen contain each a couple of aspinal pores; six others are much larger, and contain each six larger pores; these six plates are two opposite equatorial plates and four polar plates, placed in the same meridian plane (the "hydrotomical plane"); in each of these six "hydrotomical dimples" two pores are placed opposite to one another on the two edges of the leaf-shaped spine, four others being opposite in pairs on both flat sides of it. By this peculiar structure this species connects the true Hystrichaspis with Hexalaspis and Diploconus; however the twenty spines are of equal length, and the shell continues to be spherical. The twenty radial main-spines are leaf-like and compressed. The crests between the dimples are dentated by a series of small by-spines.
Dimensions.—Diameter of the shell 0.15, of the aspinal pores 0.01, of the sutural pores 0.005.
Habitat.—North Pacific, Station 240, surface.
Subgenus 2. Hystrichaspidium, Haeckel.
Definition.—Shell-surface with numerous funnel-shaped dimples (commonly one hundred and seventy-six to one hundred and eighty-two), which on the bottom are partly closed, partly perforated by one aperture (or by a pair of pores). The blind dimples are situated on the corners of the twenty plates; their number is commonly one hundred and four or one hundred and eight, sometimes more. The perforated dimples, alternating with the former, are usually seventy-two to seventy-four, sometimes more; twenty larger parmal dimples (each with a couple of aspinal pores, sometimes also with three such couples) and fifty-two to fifty-four sutural dimples, sometimes one hundred or more (each with one sutural pore). (Compare the definition of Ceriaspidium, p. [820].)
4. Hystrichaspis dorsata, n. sp. (Pl. [138], fig. 10).
Shell with one hundred and seventy-six funnel-shaped dimples, one hundred and four of which are blind and seventy-two perforated; of the latter, each of the fifty-two smaller contains a single sutural pore, each of the twenty larger a couple of aspinal pores; the elliptical aspinal pores are twice as broad as the circular sutural pores. The crests between the dimples are armed with simple scattered short by-spines; usually in the nodal points, where three combs meet, there exist three or two divergent by-spines. The twenty radial main-spines are thin and long, compressed.
Dimensions.—Diameter of the shell 0.22, of the aspinal pores 0.02, of the sutural pores 0.01.
Habitat.—Central Pacific, Station 271, surface.