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Micrhystridium Roquesi
Original description: [Valensi, 1949, p. 545] (translated from French):
Micrhystridium Roquesi nov. sp.
2 of fig. 5.
Holotype: Bathonian, flint from the vicinity of Marnes (Deux-Sèvres).
This species has a shell (2 of fig. 2) of exactly spherical shape covered with a multitude of short processes; it has the appearance of a cogwheel in optical section; the hairpin-shaped processes have a rounded or truncated end, they are traversed either by a single median axis, or by two marginal axes, the section of these processes visible on the upper face is either a diamond with marked and thickened diagonals, or a four-pointed star, or a triangle.
The shell diameter is 16 μ, excluding processes, and 19 μ with these, the processes are 1.5 μ long and almost 1 μ wide at their birth, I counted about ten of them on 10 μ from the edge of the shell.
The color of the only specimen observed is dark brown.
This curious form by its processes has no equivalent in either the Silurian or the Cretaceous.
Micrhystridium Roquesi nov. sp.
2 of fig. 5.
Holotype: Bathonian, flint from the vicinity of Marnes (Deux-Sèvres).
This species has a shell (2 of fig. 2) of exactly spherical shape covered with a multitude of short processes; it has the appearance of a cogwheel in optical section; the hairpin-shaped processes have a rounded or truncated end, they are traversed either by a single median axis, or by two marginal axes, the section of these processes visible on the upper face is either a diamond with marked and thickened diagonals, or a four-pointed star, or a triangle.
The shell diameter is 16 μ, excluding processes, and 19 μ with these, the processes are 1.5 μ long and almost 1 μ wide at their birth, I counted about ten of them on 10 μ from the edge of the shell.
The color of the only specimen observed is dark brown.
This curious form by its processes has no equivalent in either the Silurian or the Cretaceous.