Favoritos de julien-brdl

My third Blue-ray post in a week - they are my favourites!
Clearly easy to ID but not so easy to find.They are found, mostly, on the underside of Kelp (Laminaria) fronds but may occur on a few other broad fronded algae.

They are not very big in their most numerous stage, in their first few months of life. They can be tiny at 1mm to begin with, (probably in September) but by the following late spring they are 5-7mm.
I took a few home for a couple of hours, so that I could study them closely. They climbed the glass sheet I offered, so I could photograph their little undersides - pictures 5 & 6 & 7. It was here that I noticed their tendency to ALWAYS 'scurry' away from the light - perhaps they are photo-phobic?
They lose their jewelled appearance once they leave the fronds (probably after several months) to descend the stems to settle near the holdfast where they gradually take on a new 'sizeable' identity for a year or two - picture 10 shows both shells. In storms or when they can no longer hold on, they are swept away, to be predated, leaving their shells to collect on beaches. It is there where you are most likely to encounter the shell, which is drab, sometimes with passengers, (picture 8) on the outside but often highly refractive on the inside - picture 9.
This is a European species with an interesting single US (1916) record seen on this distribution map https://www.gbif.org/species/5728509 and recorded here http://www.biodiversitylibrary.org/page/27054800.
Edward S Morse was no slouch in that period https://en.wikipedia.org/wiki/Edward_S._Morse so one might wonder what happened to the specimen.
Almost finally, the blue stripes themselves offer us wonder and science here https://www.researchgate.net/publication/272838353_A_highly_conspicuous_mineralized_composite_photonic_architecture_in_the_translucent_shell_of_the_blue-rayed_limpet
And if you love science (surely you do) then this gives insite http://www.itp.uni-hannover.de/~zawischa/ITP/multibeam.html