Euchlanis is a genus of the microscopic invertebrates known as rotifers. Sometimes alternatively referred to as wheel animalcules, rotifers feature a characteristic circular arrangement of cilia at their front ends that is reminiscent of a turning wheel when they are in motion.

In addition to a ciliated corona, or head, Euchlanis species have transparent bodies and two strong toes used for swimming. They are also sheathed in a glassy shell secreted by their outer skin. Inside, each tiny individual rotifer is surprisingly complex, possessing a brain, bladder, reproductive organs, intestines, and a stomach. They are not endowed, however, with a circulatory system.

Euchlanis species are omnivorous, frequently feeding upon bacteria, debris, and small protozoans. Food particles are moved toward their mouths by the currents created by their rotating cilia. A jaw-like structure called a mastax grinds the food as it enters the stomach. When waste products accumulate, beating cilia of specialized excretory structures known as flame cells create a current that drains them into the intestines or the bladder.