Dear Neale:
For some fascinating reading on the subject, I suggest Malcolm R. Clarke's
(ed.) book: A Handbook for the Identification of Cephalopod Beaks.
Unfortunately it seems to be restricted to living forms.
Roger L. Kaesler
--
Roger L. Kaesler
Paleontological Institute
The University of Kansas
121 Lindley Hall
Lawrence, Kansas 66045-2911
(913) 864-3338 = telephone
(913) 864-5276 = FAX