Check out An Interesting Plural Quirkiness by rogersgeorge. Here is an excerpt:
Is “bacteria” singular or plural? Well, it’s plural. The singular is “bacterium.” But here’s an example of using the singular to refer to a whole bunch of the little critters. Twice:
A bacterium named Moorella thermoacetica won’t work for free. But UC Berkeley researchers have figured out it…
The full article is available here.
