<<I just  heard that some bi-valves have a "crystaline" and a "style" which
act as a mortar and pestle that they use to grind up their food. Can anyone
verify this and does anyone have any refernces ?  Many thanks.

Hank Foglino

Hi Hank.
The "crystalline style" is a single structure.  It is part of the digestive
tract of many bivalves.  It has a dual function, both releasing digestive
enzymes into the stomach, and also grinding particles by its rotating
movement in a special part of the stomach called the style sac.  For an
account of the structure I would suggest a college level invertebrate zoology
text.
Paul M.