Excerpts from Jim Conrad's
from the September 18, 2011 Newsletter
issued from Mayan Beach Garden
Inn 20 kms north of Mahahual, Quintana Roo, México
Volunteer identifier Bea in Ontario and I worked together on this but it took Bea to come up with the name EUALETES TULIPA, which is a sea snail, a marine gastropod mollusk in the family Vermetidae. Sea snails also sometimes are known as worm snails. Remember that last week's worm tubes were formed by segmented worms, like earthworms. What we have here is a mollusk, like snails and slugs -- a whole different phylum, phyla being like the phylum of animals with spinal columns (the chordates), the phylum of arthropods, the phylum of sponges, etc.
Lots of shells are similar to ours so we're not absolutely certain about the ID. However, Eualetes tulipa looks just like this, occurs in this part of the world, is known to attach to artificial substrates, and in some waters is considered an invasive species, so Eualetes tulipa is a good educated guess.
There's not much information available about Eualetes tulipa. However, now the world knows that it can ride on hardened expansion foam transported by ocean currents.