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Larger context for LACK in Corpus USbrown_UKbncw/UK_bncw.txt

  The absence of this arrangement in Nucella lapillus lends support for the separation of Nucella from Thais.   The genera Nucella, Purpura and Thais are now usually regarded as members of the family Thaididae - a name confirmed by Opinion 886 - which, in turn is part of thesuper-family Muricacea.   (Fretter & Graham (1985) prefer to retain the Thaididae within the Muricidae.)   lack >   Nucella, as we have seen, is a genus of temporate intertidal thaids, feeding for preference on barnacles and mussels (which they attack by boring a hole through the shell of their victim and subsequently inserting their proboscis through the same hole in order to feed), and lack ing a planktonic phase in their life cycle.     Except in thin-shelled populations, adults usually lay down a row of teeth along the lip of the aperture.   Thais is a genus of primarily sub-tidal, warm- water thaids, feeding on a range of molluscan prey.   They bore a hole through their victim's shell which ( at least in T. haenmastoma (Carriker, 1981)) is too small for the whelk to insert its proboscis.   There is a planktonic larval stage.   Adults do not thicken the shell lip or form " teeth" (Fretter & Graham, 1985).