Habitat.—Fossil in Tertiary deposits of the Mediterranean; plastic clay of Greece and Sicily; living in the Mediterranean and the Atlantic, Station 352, surface.
9. Distephanus sirius, Haeckel.
Actiniscus sirius, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 68.
Dictyocha sirius, Ehrenberg, 1854, Mikrogeol., Taf. xviii. fig. 59.
Each pileated piece of the skeleton is a truncated six-sided pyramid, similar to that of Distephanus speculum, but distinguished by the six broad, triangular, peripheral spines, which are articulated and connected by a thin siliceous membrane (like a web-membrane); each spine has three articulations (as in Dictyocha pentasterias).
Dimensions.—Diameter of the basal ring 0.02, of the apical ring 0.005.
Habitat.—Fossil in Tertiary rocks (Richmond, Virginia), but also living in the Atlantic Ocean, Gulf Stream, Færöe Channel, John Murray, 1880.
10. Distephanus corona, n. sp. (Pl. [114], figs. 7-9).
Dictyocha corona, Haeckel, 1881, Prodromus.
Each pileated piece of the skeleton is a truncate six-sided pyramid like that of Distephanus speculum, but differing in the number (twenty-four) of teeth or spines. Six interradial ascending beams connect the two horizontal rings between these, and six nearly vertical spines arise from the perradial corners of the upper hexagonal ring. In the same meridional (perradial) plains six larger spines descend downwards from the corners of the lower larger ring. Between these six descending spines and the six ascending beams arise from the upper edge of the lower ring twelve shorter teeth of unequal size (the right tooth in each pentagonal lateral mesh being smaller and directed upwards, the left tooth being larger and directed nearly horizontally outwards). The lower ring is nearly dodecagonal.