These strange-looking frilly edged flat spirals made of sand sometimes wash ashore on tropical beaches.
They are called sand collarsso called because they are said to resemble an old-fashioned detachable shirt or blouse collar.
Sand collars are made by the female moon snails when they lay eggs.
Moon snails, also known as the necklace shells, are a predatory sea mollusks in the family Naticidae.
The snails are known for their rather globular-shaped shells and their voracious appetite for other mollusks.
Once the shell is bored open, the moon snail proceeds to consume the flesh of the prey.
Then using mucus, she cements the sand grains together to form a flexible collar.
The female lays her eggs inside the collar and spreads it evenly around the structure.
A second layer of sand and mucus protects the thousands of eggs contained within the sand collar.
A sand collar thats intact still has eggs inside.
Image credit:www.asnailsodyssey.com
A somewhat damaged sand collar ofEuspira catena.
Photo credit:Hans Hillewaert/Wikimedia
Photo credit:Russil Wvong/Flickr
A moon snail.
