Never mind, Ken, it comes to us all eventually. I'm always losing my glasses, too, and wondering why I've just gone into a room when I knew I went there for a particular reason...
Anyway, here is a stacked image of a similar diatom, this time in DIC for comparison:

Microscope: Zeiss Standard 16
Ocular: Zarf G9 photo adapter
Objective: Leitz NPL Fluotar 40/0.7 ICT
Substage: Leitz ICT
Stack of 18 images/Helicon Focus 4.40
Flash