staircase shell

from The Collaborative International Dictionary of English v.0.48

Staircase \Stair"case`\ (st[^a]r"k[=a]s`), n.
   A flight of stairs with their supporting framework, casing,
   balusters, etc.
   [1913 Webster]

         To make a complete staircase is a curious piece of
         architecture.                            --Sir H.
                                                  Wotton.
   [1913 Webster]

   {Staircase shell}. (Zool.)
   (a) Any scalaria, or wentletrap.
   (b) Any species of {Solarium}, or perspective shell.
       [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Wentletrap \Wen"tle*trap`\, n. [D. wenteltrap a winding
   staircase; cf. G. wendeltreppe.] [Obs.]
   Any one of numerous species of elegant, usually white, marine
   shells of the genus Scalaria, especially {Scalaria pretiosa},
   which was formerly highly valued; -- called also {staircase
   shell}. See {Scalaria}.
   [1913 Webster]

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