Infusoria is an obsolete collective term for minute aquatic creatures like ciliates, euglenoids, protozoa, and unicellular algae that exist in freshwater ponds. The first type exists in the common fresh-water organism known as Euglena. The spindle-shaped body is surrounded by a delicate cuticle perforated at one point, where a funnel-shaped depression, the gullet, leads into the soft protoplasmic interior. From the base of this depression the protoplasm is drawn out in the form of a delicate ship-like process known as the flagellum. Shown here is Flagellate Infusoria (fig 8A); (c) pulsating vacuole; (e) eye-spot; (g) gullet; (n) nucleus; (t) flagellum.