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Polysolenia arktios Nigrini, 1970

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Polysolenia arktios Nigrini, n.sp. Pl. 1, figs. 4, 5; Fig. 4

Description. Shell smooth, spherical with numerous randomly arranged, subcircular and irregular pores of varying size. Shell very spiny, one or more poreless spines up to one-third the length of the shell diameter project outward from most pore margins. Spines may fork, or 2 or more spines arising from a single pore may meet at a point; they may be needle-like or flat, blunt projections. Rarely, specimens with an extra-cortical shell have been observed.

Dimensions (based on 20 specimens). Shell diameter 103 to 238 Ám. Maximum length of spines 48 Ám.

Discussion. This species appears to be closely related to P. spinosa , but its restricted distribution in Subarctic sediments (compare Figs. 3 and 5) seems to warrant a taxonomic distinction. Intraspecific variations and the relationship between species can, of course, only be fully determined by examination of whole colonies.
Nigrini 1970











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