In 1947 I learned what a piddock is, it was in a book called It's Fun Finding Out by Bernard Wicksteed helped in the more scientific investigations by Chapman Pincher. The only mention of a microscope is of an American who spent a lifetime studying snowflakes, he caught them on black velvet, rushed indoors and put them under a microscope, he classified more than 5,000 different patterns. This little book made quite an impression on me whetting my curiousity to find out about anything of which I had little knowledge.
Forty years on in 1987 I made photomicrographs of a number of slides of arranged diatoms loaned to me for the purpose by Bill Boorn of Folkestone, Kent. One of these slides, described as diatoms from Japan, had some forms on it that obviously were not diatoms; some looked like little anchors and some little plates with holes. Now as most regular readers of Micscape will know I spend most of my time studying freshwater algae particularly the desmids. But this was something of a challenge, it would be fun finding out what they were. If not fun, finding out is very satisfying. Where to start? The double headed 'anchors' reminded me of pictures I had seen of sponge spicules.
| I eventually found the answer in The Microscope & it's Revelations by W. Carpenter — revised by W. Dallinger 1891, 7th Edition page 819. They are plates that are attached with an anchor in the skin of Holothuroidae the double-ended anchors may be as I first thought sponge spicules. Fig. 1 right is of the diatom + arrangement. The photo' was taken using a X20 flat field objective with a X6 eyepiece at 1/30th sec. on Kodak film using 40 cyan and 40 magenta filters. |  |
| The photo's were put away and forgotten until recently when in the Micscape paper version I saw a drawing by Wim van Egmond (shown right) that looks like a Holothurian plate so I looked out the photomicrographs to compare with Wim's drawing. I am still not sure about Wim's plate as he gives no indication of the size of the object. |  |
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As you can see by the photo' the Holothurian plates are about the same size as some of the diatoms and smaller than the central one which gives some idea of the size. Fig. 2 left is a sketch of a plate and an anchor drawn from the photo'. Well it's fun finding out, but am I right? |
| The author William Ells, in his friend Don Bruce's study. |  |
Editor's notes: if you don't know what a 'piddock' is, as Bill says, have fun finding out!
Comments and feedback to Bill Ells are welcomed.
First published in August 1998 Micscape Magazine.
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