Among Cambrian small shelly fossils, a number of tiny, often septate, conoidal tubes have been suggested to be of cnidarian affinity, namely, paiutiids, quadriradial cari-nachitiids and hexangulaconulariids, triradial anabaritids, and byroniids (for reviews, see Conway Morris and Chen 1989, 1992; Bengtson et al. 1990; Rozanov and Zhuravlev 1992). Except forbyroniids, these animals are restricted to the Early Cambrian. Most of them are suggested to be sessile forms. Tentacle-bearing Cambrorhytium might be a cnidarian possessing an organic-walled tube (Conway Morris and Robison 1988). It is worth noting that phosphatized spheroids, in Nemakit-Daldynian strata containing anabaritids, resemble nonplanktotrophic cnidarian actinula larvae (Kouchinsky etal. 1999).
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