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Phylum Mollusca > Class Gastropoda > Family Cassidae
Japanese bonnet snail
Phalium/Semicassis bisulcata

Family Cassidae
updated Oct 2016

Where seen? This beautiful snail was seen on Cyrene Reef. The one seen on Changi is possibly also a Japanese bonnet snail.

Features: 5-7cm long. Shell typical helmet shape with a large body whorl and tiny spire, thus resembling a bonnet. The shell has spiral ribs, 25-40 on the body whorl. Outer lip reflected, toothed on the inner edge. White, cream, pink or blue-grey. Sometimes unmarked, sometimes with 4 or 5 spiral bands of brown spots. It has a white body and the sole of the foot is dark. The operculum is fan-shaped and pale yellow.

What does it eat? According to Gosliner, it presumably feeds on heart urchins including the Tiny maretia heart urchin (Maretia planulata).

Cyrene Reef, Jun 12

Changi, May 11

Japanese bonnet snails on Singapore shores

Photos of Japanese bonnet snails for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map

Changi, Feb 09
Photo shared by Loh Kok Sheng on his blog.

Cyrene Reef, Mar 09
Photo shared by Chim Chee Kong on his flickr.

Cyrene Reef, Mar 09
Photo shared by Loh Kok Sheng on his blog.

Cyrene Reef, Jun 11

Photo shared by Loh Kok Sheng on flickr.

shared by Neo Mei Lin on her blog

Grateful thanks to Chim Chee Kong for identifying this snail on his flickr.



  • 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.
  • Gosliner, Terrence M., David W. Behrens and Gary C. Williams. 1996. Coral Reef Animals of the Indo-Pacific: Animal life from Africa to Hawaii exclusive of the vertebrates Sea Challengers. 314pp.
  • Abbott, R. Tucker, 1991. Seashells of South East Asia. Graham Brash, Singapore. 145 pp.
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