Thick topshell

Thick topshell

Thick topshell ©Nigel Phillips

Thick topshells

Thick topshells ©Nigel Phillips

Thick topshell

Scientific name: Phorcus lineatus
The thick topshell is a common sight on rocky shores in Wales and South West England.

Species information


Height: Up to 3cm

Conservation status


When to see

January to December


The thick topshell, also known as the toothed topshell, is found on rocky shores as far south as Morocco. North Wales is the upper limit of its range. They live on the mid shore, grazing on algae on the rocks at high tide.

How to identify

A conical whorled shell, pale grey in colour with a maroon zig-zag pattern and mother of pearl on the inside. It can be distinguished from similar, snail-like periwinkles and topshells by the 'tooth' just inside the mouth of the shell.


Found on rocky shores around Wales and South West England.

Did you know?

Topshells get their name because the shell is shaped like an old-fashioned spinning top.

How people can help

When rockpooling, be careful to leave everything as you found it - replace any rocks you turn over, put back any crabs or fish and ensure not to scrape anything off its rocky home. If you want to learn more about our rockpool life, Wildlife Trusts around the UK run rockpool safaris and offer Shoresearch training - teaching you to survey your local rocky shore. The data collected is then used to protect our coasts and seas through better management or through the designation of Marine Protected Areas. The Wildlife Trusts are working with sea users, scientists, politicians and local people towards a vision of 'Living Seas', where marine wildlife thrives. Do your bit for our Living Seas by supporting your local Wildlife Trust or checking out our Action Pages.