Sometimes instead of using the scoop and dump method I gather the grit in a metal strainer. It’s kind of like panning for gol."/>
Sometimes instead of using the scoop and dump method I gather the grit in a metal strainer. It’s kind of like panning for gol."/> Buttons of the sea | News, Sports, Jobs - SANIBEL-CAPTIVA - Island Reporter, Islander and Current
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Buttons of the sea

By Staff | Oct 16, 2009

One of my favorite shelling activities involves “scouring” the first foot or so of the surf. Using a shelling net, the “shell grit” in the shallow water is scooped up and dumped on the beach with the hope of discovering a wentletrap or other special small species like the subject of this week’s column, Modulus modulus, also known as the button snail or Atlantic modulus.

Sometimes instead of using the scoop and dump method I gather the grit in a metal strainer. It’s kind of like panning for gold. By letting the water pass over and run through the metal screen the sand is washed away making it easier to identify potential treasures.

Every time a Modulus modulus appears in my shell net, I’m reminded of a round basket-weave type container my grandmother kept her buttons. As a child, rummaging through this treasure chest was a delight. It’s amazing how some of the simplest experiences in life are the ones remembered most vividly.

The button snail is a small, knobby, bumpy, top-shaped gastropod about a half-inch in diameter and a half-inch tall. The upper whorls are elevated and curve upward with brown or purple slanted markings on a cream background. Occasionally the entire shell may be cream colored or light brown with darker colored markings. The body whorl is much larger than the upper whorls. Each whorl is outlined with a spiral cord. The shells opening, also called the aperture is almost perfectly round. The shells central pillar called the columella, has a tooth-like structure at the base.

The animal that produces this shell is green and has a long, narrow snout. A thin, round operculum serves as this mollusk’s protection from predators like grunts and wrasses.

The first time I remember finding one was on the Outer Banks buried in beach drift, a common location for an empty shell. The sand flats to the east of the Sanibel Bridge are one of my favorite spots for watching a live button snails almost hidden by the thick grasses in fairly shallow water. The snail slithers along the blades of grass almost effortlessly thanks to a layer of mucous it secretes. Their range extends from North Carolina to Brazil. Empty shells serve as home for large numbers of hermit crabs.

Fertilization is internal. Jelly-like cylinders of eggs are placed on the sea grass by the females. About three weeks later the juveniles crawl away from the egg masses.