sentinel. A person or special body of persons assigned to provide protection or keep watch over, for example: guard, lookout, picket, protector, sentry, ward, watch.
Victrola. Originally, a phonograph from the Victor Talking Machine Company, Camden, NJ, but it eventually became more of a generic term for any brand of phonograph.
A radula is a tongue-like ribbon that helps the snail scrape or cut its food before it swallows it. The image, taken at 200x zoom, was an honorable mention in the 2013 Nikon Small World photomicrography competition.