noun
bell animalcule; Vorticella
A tiny aquatic organism shaped like an inverted bell; often used in biology contexts. The name literally means 'hanging-bell insect', though it is not an insect.
顕微鏡で池の水を見ると、釣り鐘虫がたくさん見えた。
When I looked at the pond water under a microscope, I saw many bell animalcules.
From 釣り鐘 (つりがね, 'temple bell') + 虫 (むし, 'insect, bug'), referring to its bell-like shape. The exact origin is uncertain, but the name is descriptive.