Collotheca is a genus of rotifer that feeds by extending long hair like structures called setae, in which it traps its prey. In the case of this sessile (that is, not swimming) species ornata, the prey is largely made up of bacteria and tiny algae.

Here you can see the full process of opening up its mouth, made up of 5 total lobes (not all seen clearly in this focal plane), and extending all its setae, before being startled and contracting back into its hiding spot. Even the lightest touch on the microscope stage would cause it to contract; those are some sensitive whiskers.

Euglenids are some of my favourite creatures. Most of them swim along with the help of a flagella that they whip around in front like a propellor.

But this one can barely get off the surface. This absolutely massive Euglenid appears to be roughly 200 µm, much greater than the types I normally see. Based on its very short flagellum and worm-like shape and behaviour, I’m tentatively identifying it as Euglena ehrenbergii. Shown here in timelapse to emphasize the twisting motion and shape morphing, known as metaboly.

Also visible here are Coleps, Phacus, Closterium, diatoms, some small loricate euglenids, and a very quick drive by of some species of rotifer.

Gastrotrichs come by their name honestly and are commonly known as hairy bellies (derived from Ancient Greek γαστήρ/gastēr for stomach and θρίξ/thrix for hair).

This is an example of Chaetonotus, a genus of gastrotrich, that seemed to get itself stuck on a piece of debris (like a poor kid putting his head through a fence). This gave me a chance to oil the slide and take a closer look at its scales and hairs. The pharynx and digestive system are also clearly visible.

Vorticella is a genus of single celled, bell-shaped ciliates that spend most of their lives filter feeding, anchored by a tether that snaps back like the world’s tiniest spring. The snap happens so fast it’s almost impossible to see – at a human scale, it would mean going from a standstill to the speed of sound in one second.

While Vorticella are solitary organisms, they tend to cluster together, as seen here in a long slow pan along the root of a single piece of duckweed.

Water doesn’t tend to move much on a microscope slide, but sometimes an air bubble will burst and everything will rush past in a tiny torrent. This single celled algae, part of the genus Mesotaenium characterized by its gelatinous capsule and leaf-shaped chloroplast, just went along for the ride.

Thuricola is a genus of loricate peritrich, meaning a ciliate that anchors itself to feed and builds a protective shell around its soft body parts. The defining characteristic of this genus is the small “valve” or trapdoor that the individual zooids push out of the way when exiting the lorica. This valve, called an operculum, snaps shut when the zooids retreat, giving them protection against predators or debris.

In the second part of the video, we zoom in for a closer look at the moment the pair of zooids push past the operculum. Eventually this home gets too big for the two of them, and one undergoes a metamorphosis into a freely swimming organism and heads off to find a new place to settle down and build a home all over again.

Locomotion in the microscopic world takes many forms. Here we have a large single-celled ciliate from the genus Holophrya, characterized by its ovoid shape and large mouth at the tip of the organism. Ciliates glide along by beating rows of many small hairs called cilia.

We also see here a tardigrade, a multicellular creature with proper organs and a digestive system. Tardigrades move by crawling or scrambling along using their four pairs of clawed legs.