• (n.) The anterior prolongation of the guard of the phragmocone of belemnites and allied fossil cephalopods, whether horny or calcareous. See Illust. of Phragmocone.
Found on
http://thinkexist.com/dictionary/meaning/proostracum/
Pro·ös'tra·cum noun ; plural Proöstraca . [ New Latin , from Greek ... before + ... shell of a testacean.] (Zoology) The anterior prolongation of the guard of the phragmocone of belemnites and allied fossil cephalopods, whether horny or calcareous. See Illust. of
Found on
http://www.encyclo.co.uk/webster/P/174
No exact match found.
