Patella caerula o Patella intermedia?

[Emma]

Hello again!

Does anybody have a guide or can offer me some advice on how to classify my Mediterranean Patella. I have followed all the advice offered by books on how one is irridescent and the other is not, but I'm sorry to say I still have no idea. So, like a few weeks before, I'm asking the old question of whether these specimens are Patella caerula or Patella intermedia. They are all from the coast of Tarragona.
Any help would be very useful!

Thanks,

Emma.

[dave r]

I would say they were all cerulea. Intermedia has a much darker shell with more colourful interior.

[Emma]

Thanks Dave!!