- (malacology) A marine univalve shell of the genus Bulla and allied genera, belonging to the Tectibranchiata molluscs.
- The headshield slugs of genus Bulla, belonging to the clade Cephalaspidea of gastropods.
- Bulla (gastropod) on Wikipedia.Wikipedia:Bulla (gastropod)
- Bulloidea on Wikispecies. Wikispecies: Bulloidea
- Bulla (genus) on Wikimedia Commons. Wikimedia Commons: Bulla (genus)
Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.