They are called a sand collar and are made by Moon Snails. The eggs are
molded by the shell curvature as the eggs are cemented with sand. The
small eggs are in the central jelly area, covered by both sides with
sand. Here in Southeast Alaska the snails use the available sand and are
different color according to the color of that particular beach. Each
species has its own characteristic color shape.
 
 -----Original Message-----
From: Conchologists of America List
Sent: Wednesday, June 10, 1998 12:28 PM
To: ScottW; [log in to unmask]
Subject: Sharks nest
 
Hi shellers,  I am looking for the "parent" of what we used to call a
"sharks
nest" found around Newport Beach bays, in calm ,shallow water.  It is a
collar
of sand cemented togeather with some sort of mucus, with a hole in the
middle.
As kids, we used to think sand sharks made them for their eggs.  But I
have
heard that the moon snail really makes them for their eggs. Does anyone
know
about this curios little nest? Thanks ,Leslie