Randomly browsing the charity shop bookshelves invariably reaps unexpected rewards. “The Sea Shore” by C.M. Yonge was a fabulous find for me. First published in 1949, this densely-written paperback, jammed full of information and Latin scientific nomenclature, is not an easy read. It is quite the contrast to my only other seaside guide, the 1955 edition of I-SPY AT THE SEASIDE. Much, I suspect, has changed since both were written, but both, in their own way, are still mines of fascination for the coastal wanderer.

C.M. Yonge provides some lovely linear illustrations and diagrams, tide maps and exquisitely delicate drawings of rippling seaweed varieties and fascinating alien life forms, cross-sections of rock-boring bivalves, cliff-faces showing the vertical distribution of the acorn barnacle, encrusting hydroids on the surface of a whelk shell and the kidneys, heart, stomach and reproductive organs of the sea squirt. The sea shore is indeed a mysterious place. Those jelly blobs I’d often noticed on my beach walks have a heart and kidneys – amazing! I texted my friend excitedly with the news of this discovery. “I hope they don’t have a brain!” she texted back. She was worried to think she may have hurt them when she had inadvertently stepped on one, getting squirted by a strong avenging jet of water, straight from the kidneys, no doubt.

I suspect that the answer to my friend’s anxious question is, unfortunately yes or, if not exactly a brain, according to C.M. Yonge, sea squirts do, like us, have a central nervous system and, like us, they are members of the chordates which means that, at some point in their development, they have something resembling a spine, so they do have feelings. There is more than meets the eye to those little bags of jelly we find washed up on the beach.

So, my curiosity piqued, one day last week I decided to make my walk into a hunt for sea squirts. I splashed happily through the wet sand, searching for jelly blobs, but very soon forgot what I was there for, as aimlessness is the whole point of walking, as far as I’m concerned, and I’m easily distracted. A parcel of oystercatchers fished in the shallows and a wedge of Brent geese bobbed on the water, keeping up their incessant gossip, before a dog came galumphing joyously through the waves. Here in Ryde, the Brent geese are regular visitors over winter. They, like the neat little running birds called sanderlings, fly in from the Arctic regions, resting and feeding themselves up ready for the long flight home in spring. My heart always knots up, to be honest, when I see them disturbed by dogs or humans, and having to waste their valuable calorie intake in a panicked escape.

Having completely forgotten I was looking for jelly blobs, I did, of course, find some. Not sure they were sea squirts. The yellow ones might be a colony of them. The pinkish one camouflaged in the sand is a more exotic creature all together, with delicate gelatinous frills and flaps and raspberry-ripple streaks of magenta. I didn’t poke either of these extraordinary life forms to see what would happen, and perhaps risk getting squirted in the eye, but left them to sit and perhaps to think in peace, awaiting the turn of the tide.