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figure 35.2 Circopus sexfurcus
with six spines, all set at 90° apart.
Reproduced from Bernard Richards, ‘The
morphogenesis of Radiolaria’, MSc Thesis,
University of Manchester, 1954, with
thanks to Dr Richard Banach. Original
image taken from Ernst Haeckel, Report of
the Scientific Results of the Voyage of H.M.S.
Challenger During the Years 1873–76,
Volume 18.figure 35.3 Circopurus octahedrus with
six spines and eight faces.
Reproduced from Bernard Richards, ‘The
morphogenesis of Radiolaria’, MSc Thesis,
University of Manchester, 1954, with thanks to
Dr Richard Banach. Original image taken from
Ernst Haeckel, Report of the Scientific Results of
the Voyage of H.M.S. Challenger During the Years
1873–76, Volume 18.As the spherical newborn radiolarian grows, ‘spines’ (a kind of spike) develop from the sur-
face in pre-determined positions. The resulting shapes give rise to six sub-species of Radiolaria.
The length of the spines is usually equal to the radius of the main spherical body and they are
symmetrically positioned over the sphere. If the body has only two spines they are situated at
the north and south poles. There are no three-, four-, or five-spined versions. The six-spined
version has the spines placed 90° apart over the surface of the sphere—two at the poles and four
around the equator. Other versions have twelve or twenty spines. The shapes taken by these
types of Radiolaria resemble some of the regular mathematical solids (Figs 35.1–35.6).