from the GNU version of the Collaborative International Dictionary of English
- n. An amoebalike protozoan with a chitinous shell resembling an umbrella.
from The Century Dictionary and Cyclopedia
- n. A genus of amœboid protozoan organisms having a kind of carapace or shell, the type of a family Arcellidæ.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an amoeba-like protozoan with a chitinous shell resembling an umbrella
Sorry, no etymologies found.
After from five to twenty minutes, the specific gravity of the arcella is so much lessened that it is lifted by the water with its pseudopodia, and brought up against the upper surface of the water-drop, on which it is able to travel.
If we bear these circumstances in mind, we can almost always tell whether an arcella will develop air-vesicles or no; and if it has already developed them, we can tell whether they will increase or diminish ...