phragmocone

English

Etymology

From phragmo- +‎ cone.

Noun

phragmocone (plural phragmocones)

1. (malacology) The chambered portion of the shell of certain cephalopods, divided by septa into camerae. [from 19th c.]
   • 2017, Danna Staaf, Squid Empire, ForeEdge, →ISBN, page 37:

     This ability to continuously add new buoyancy chambers to their phragmocones allowed ancient cephalopods to reach truly stupendous sizes.