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]WordNet (r) 3.0 (2006):
phragmacone n 1: the thin conical chambered internal shell (either straight or curved) of a belemnite [syn: phragmocone, phragmacone]