Sea-potatoes

Echinocardium cordatum -a heart-urchin. Lower image shows the underside with the mouth visible in centre.

Due to pressure of work, visitors, holidays and rotten weather, haven't had time to post in the last couple of months. However, yesterday was a lovely warm and sunny day, so headed early to the beach. It was low tide and I found several of these strange looking objects. They were very fragile and some were broken. I thought they might be the test of a sea urchin, and on looking them up found that they are known as sea-potatoes, only they are animal not vegetable. They are known as heart-urchins due to their shape. They are adapted for burrowing and are usually found about 15cm deep in the sand (perhaps that's why they are known as sea-potatoes). When alive they are densely covered in yellow-brown spines.