The sea is a trove of remarkable treasure, usually cryptically camouflaged in reefs or gracefully free-swimming in the blue. Whichever form of locomotion or seemingly inanimate form of the creature, every finding is worthy of identification. Just as so many species are named after the discoverer, every diver should take up photography to ‘collect’ species and share the findings, as this can be a rewarding pursuit. I have been blessed with an inquisitive mind to ask about the oddities of these aquatic inhabitants.
While exploring the reef of Mataking island, one such creature I found to be alien-like is the vermetid snail, a kind of Scaled Worm Snail from the class of gastropods and genus of Serpulorbis. This specie builds a tube that is uncoiled, or has only irregular, loose whirls that are fixed to the ground.
In this tube, the ‘tube’ worm (which is actually a snail) lead a relatively secure, sedentary life, showing only its finely branched tentacles at the top. The tentacles are not only very colourful, they are often very captivating as you would be drawn to figure out what animal they could possibly be. Due to the similarity to such marine worms (particularly to the group of Serpulidae), the name of the tube-building molluscs here is worm shells, worm snails or vermetid snails. Originated from the Latin word vermis, which refers to worms; possibly how Vermicelli was derived or vermin when you describe pests!
Vermetids start their life like "normal" snails, with a small shell that they carry around in a short period of free-living life. Their first larval shells are still tightly and spirally coiled. Eventually they cement their shell to a hard substrate. In the growing stage, its tube may take a loosely coiled or meandering form, laying over the substrate.
Their tentacles are not meant to catch food. They have only two, albeit very large ones. Instead, they gather food by releasing a net of sticky mucus strands into the water. After a while, like fishermen, they pull the entire mucus structure back and eat it - with all the planktonic goodies trapped within. To fabricate the net, the snails have a large mucus gland right near the two tentacles that can expel the mucus through the tentacular grooves. Should they sense danger lurking outside, vermetid snails retreat their tentacles and close the tube by a proteinaceous door, kind of like an operculum in sea shells.
Common Name – Scaled Worm Snail
Genus – Serpulorbis
Specie – grandis
Location:- Mataking Island
Description:- 127mm long, 13mm wide. Attached to solid substrate. Irregularly shaped, open end upturned.
Habitat:- Attached to rocks and pilings in protected places; between high and low tidal zones to water 20metres deep.
