Shell & gizzard plates of Philine orientalis

Dear Koh,
I am glad to see my prediction about the shape of the gizzard plates proved correct. There seems to be an evolutionary sequence in the genus from 'primitive' species with small uncalcified plates all of similar shape and size, through species with small equi-sized calcareous plates [see Philine auriformis], to the large muscular species like this one with large calcareous plates, two of which are large and mirror images of each other, and a third smaller one of a more symmetrical shape. I have also included a close-up of the inside of one of the large gizzard plates to show the pair of microscopic holes they usually have. I have no idea of their function - if any.

As you can see in the photo alongside, the gizzard plates can often be seem through the body wall of the living animals.
Best wishes,
Bill Rudman