Stephensonactis Panikkar 1936 p. 231

Haliactiidae with long, vermiform body, distinctly divisible into three regions, a more or less physa-like base, a broader scapus provided with rows of cinclides and with nematocysts arranged in groups, and a narrow capitulum. No sphincter. Tentacles arranged in 5-6 cycles. Longitudinal muscles of tentacles and radial muscles of oral disc ectodermal. 2 siphonoglyphs. Mesenteries divisible into macro- and microcnemes, more numerous distally than proximally. 6 pairs of macrocnemes. Retractors of the macrocnemes as those of Phytocoetopsis, parietal muscles rather well developed. Acontia thick, long, arranged in the usual manner, with basitrichs and probably microbasic amastigophors ("penicilli").

Species

S. ornata Panikkar 1936

Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1

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