Synaptidae

Burmeister, 1837

17 Genera, 2 monotypic; 166 species

Tentacles with stalk cylindrical or terete, not becoming widened distally, either with digits along each side for most of its length (pinnate), or with only one or two digits on each side near the tip (digitate), or without digits at all (simple). Calcareous deposits usually anchors and perforated plates, often accompanied by irregular, curved rods or minute particles (miliary granules), but any of these may be wanting. Hermaphroditic so far as known. (Clark, 1907)

Body elongate. Calcareous ring often with more than 5 inter-radial pieces; radial pieces often perforate. Small ciliated funnels usually present in body cavity. No Cuvierian organs. Pair of statocysts at the base of each radial nerve. Calcareous deposits mainly anchors and anchor plates, wheels or sigmoid bodies. (Mortensen, 1927)

Calcareous deposits in the form of anchors or anchor plates. Tentacle stalk cylindrical or terete, not becoming widened distally, either with digits along each side for most of its length (pinnate), or with only one or two digits along each side near the tip (digitate). (Pawson, 1965)