phragmacone

from WordNet (r) 3.0 (2006)

phragmacone
    n 1: the thin conical chambered internal shell (either straight
         or curved) of a belemnite [syn: {phragmocone},
         {phragmacone}]

from The Collaborative International Dictionary of English v.0.48

Phragmocone \Phrag"mo*cone\, n. [Gr. ?, ?, a fence, an inclosure
   + ? a cone.] (Zool.)
   The thin chambered shell attached to the anterior end of a
   belemnite. [Written also {phragmacone}.]
   [1913 Webster]