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Phylum Mollusca > Class Gastropoda
Bazillion snail
Batillaria zonalis
Family Batillariidae
updated Oct 2016
Where seen? This snail is commonly encountered in large numbers on many of our shores. In shallow sandy and slightly muddy areas which are sheltered from strong waves and currents, including the bottom of man-made lagoons, usually near the mid-water mark. It is said that they can reach densities of hundreds of snails per square metre. It was previously placed in the Family Potamididae.

Features: 2-3cm.
Shell conical with pattern of white spiralling lines with finer lines and large bumps. Shell opening oval, large, flared with upturned spout at the tip. Operculum is circular and made of a horn-like material with several circular whorls that are usually quite visible. The animal has fine bars on its mottled body, also on its proboscis and tentacles. Eyes at the base of the tentacles.

Sometimes, they are seen in 'bands' of many individuals. Small ones have been seen floating on the water surface with the broad foot.

Sometimes mistaken for Creeper snails (Family Cerithiidae).
More on how to tell these snails apart.

What does it eat?
It eats detritus and grazes on the microscopic algae that grow on the bottom.

Sisters Islands, Feb 06

Upturned siphonal canal near the opening

Sometimes forming bands of many individuals.
Tanah Merah, Dec 09

Circular operculum made of horn-like material.

Seen floating on the water surface.
Tanah Merah, Jun 09

Tanah Merah, Sep 13

Mottled body with fine bars.
Tanah Merah, Sep 13

Bazillion snails on Singapore shores

Photos of Bazillion snails for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map

Pulau Sudong, Dec 09

Family Batillariidae recorded for Singapore
from Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore.

  Family Batillariidae
  Batillaria zonalis (Bazillion snails)



  • Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore (pdf), Raffles Museum of Biodiversity Research, National University of Singapore.
  • Tan, K. S. & L. M. Chou, 2000. A Guide to the Common Seashells of Singapore. Singapore Science Centre. 160 pp.
  • Abbott, R. Tucker, 1991. Seashells of South East Asia. Graham Brash, Singapore. 145 pp.
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