pseudosiphonn.
/ˈs(j)uːdə(ʊ)ˌsʌɪfn/, U.S. /ˈsudoʊˌsaɪf(ə)n/ Zoology.
A structure resembling the siphon of a mollusc; esp. (in some bivalves) a projection of the mantle bearing a groove rather than forming a tube; (in brachiopods) a channel formed by setae extending from the edge of the mantle; (in some fossil cephalopods) a linear trace in the rock which fills the opening of the shell, continuous with the fossilized siphuncle but not part of it.
ΚΠ
1883 Hyatt in Proc. Boston Soc. Nat. Hist. XXII. 258 The central trace compares with the pseudosiphon of the plug.
1890 Amer. Naturalist 24 1138 (caption) Pecten irradians..showing foot, tentacles, eyes, and excurrent pseudosiphon.
1992 Limnol. & Oceanogr. 37 1557/1 Scallops may not be representative of other active suspension feeders because their inhalent and exhalent pseudo-siphons may not experience the same flow fields.
1994 Philos. Trans. (Royal Soc.) B. 351 258/1 A biconvex funnel accommodating the three setal pseudosiphons fashioned for the exchange of water within the mantle cavity [of the brachiopod Lingula].
Derivatives
ˌpseudoˈsiphonal adj. rare.
ΚΠ
1890 Cent. Dict. Pseudosiphonal, of, pertaining to, or resembling the pseudosiphon of cephalopods.
1994 Philos. Trans. (Royal Soc.) B. 346 261/1 The anteromedial sectors of the shells of some extinct species were less flexible..and, therefore, less well-adapted to accommodating any pseudosiphonal system that may then have existed.
This entry has been updated (OED Third Edition, September 2007; most recently modified version published online March 2022).
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n.1883