To quote Wikipedia ( http://en.wikipedia.org/wiki/Sea_mouse )
' The sea mouse, (Aphrodita aculeata), is a marine polychaete worm found in the North Atlantic, the North Sea, the Baltic Sea and the Mediterranean. The sea mouse normally lies buried head-first in the sand. It has been found at depths of over 2,000 metres (6,600 ft).
Its body is covered in a "dense mat" of setae (hairlike structures) from which the name "sea mouse" derives. '
It is these setae that are mounted in the slide on a black background. The setae appear iridescent in normal daylight in the living creature. Again to quote Wikipedia :
'The spines, or setae, that emerge from the scaled back of the sea mouse are one of its unique features. Normally, these have a red sheen, warning off predators, but when the light shines on them perpendicularly, they flush green and blue, a "remarkable example of photonic engineering by a living organism". These colors are believed to be a defence mechanism, giving warning to potential predators. The effect is produced by many hexagonal cylinders within the spines, which "perform much more efficiently than man-made optical fibres".'
I used incident polarised light on a Leitz Ortholux with the Ultropak incident light attachment http://www.photomacrography.net/forum/v ... 450#139450 with a Leitz X 6.5 UO epi objective. Rotating the polariser or adding a Perspex retarder changed the colours through red, green and blue as described above and something of the structure of the setae could be seen.
The first two images are sections from a 28 image stitch made with Microsoft ICE.
The following two pictures are crops to show more detail of the structure of the setae.
