Euglena
(Steel plate and bar)

“I took up a little of it in a glass phial; and examining this water next day, I found floating therein divers earthy particles... These animalcules had divers colours, some being whitish and transparent others with green and very glittering little scales… the motion of most of these animalcules in the water was so swift, and so various, upwards, downwards, and round about, that 'twas wonderful to see.” van Leeuwenhoek 1674. Letters to the Royal Society of London.

“composed from a system of fine, parallel longitudinal stripes, located tightly next to each other, that run from the front end to the back end of the body in left-wound, widely extended spiral lines and that emerge clearly and rib-like to the outside during contraction.” Muller 1786. Animalcula Infusoria

Euglena were likely the first protists to be observed under a microscope. Antoni van Leeuwenhoek and his homemade microscope observed them in lake samples he had collected. There are approximately 800 species of Euglena, some are photosynthetic and others are heterotrophic. This made classification difficult. Were they plants or animals? Ernst Haeckel added a third kingdom, the Kingdom Protista, to solve this problem.

Trichomitopsis
(Steel plate and rod)

“Forward swimming is characteristic of the elongated form. The membrane undulates with such rapidity that when at maximum speed the eye cannot detect the separate curves.” Kirby 1931. Univ. Calif. Publ. Zool.

Another protist that helps to digest wood. This protist lives here in Vancouver within the local dampwood termite, Zootermopsis. Its most striking feature is its undulating membrane that looks like a spinning saw blade providing a means to move about the termite’s gut contents.

Didinium
(Cast brass, copper and brass wire)

“If, while swiftly turning in the water, the Didinium happens in the neighborhood of an animalculum, say a Paramecium, which it is going to capture, it begins by casting at it a quantity of bacillary corpuscles which constitute its pharyngeal armature. The Paramecium immediately stops swimming, and shows no other sign of vitality than feebly to beat the water with its vibratile cilia; on every side of it lie scattered the darts that were used to strike it. Its enemy then approaches and quickly thrusts forth from its mouth an organ shaped like a tongue… then gradually brought near by the recession of this tongue-shaped organ toward the buccal aperture of the Didinium, which opens wide, assuming the shape of a vast funnel in which the prey is swallowed up.” Balbiani 1873. Arch. d Zool. Exp.

Didinium is fast-moving ciliate and a voracious predator that uses a specialized feeding structure (trichocysts) to entangle and paralyze its prey. It is capable of engulfing prey that is larger than itself. When food becomes scarce Didinium will encyst (similar to hibernation) until prey becomes available.

Dinoflagellate
(Steel plate and rod)

“Some of the water placed in a glass was of a pale reddish tint; and, examined under a microscope, was seen to swarm with minute animalcula darting about, and often exploding. Their shape is oval, and contracted in the middle by a ring of vibrating curved ciliæ.” Darwin 1839. The Voyage of the Beagle.

Infamous for causing red tides, dinoflagellates can bloom to concentrations of more than a million cells in a milliliter of water! They can produce toxins that are harmful to fish and shellfish and those that feed on them, including humans. Not all dinoflagellates are harmful however, certain species produce light when disturbed through a process called bioluminescence.

Trichonympha

"The arrangement of the long cilia, clothing the body, reminded him of the nymphs in a recent spectacular drama, in which they appeared with their nakedness barely concealed by long cords suspended from the shoulders, and this arrangement has suggested the name applied to the parasite." Leidy 1877. Proc. Acad. Nat. Sci. Philadelphia.

Trichonympha was the first of the many protists in termites to be observed by one of the fathers of protistology, Joseph Leidy. His name cast a mold for the naming of other large protists, many of which end in “-nympha”. What is less known, however, is that his name was inspired by a “spectacular drama” and more specifically some scantily clad ladies in this drama. Trichonympha is a Parabasalian protist, and one of the most widespread symbionts in termites and cockroachs, being found in hundreds of host species around the world. It is large and distinctive, covered in hundreds to thousands of flagella, the hair-like waving appendages usually used for swimming. These four pictures reconstruct a Trichonympha cell: on the left is the fanned ‘cap’ or operculum, the middle two show details of their thousands of elaborately organized flagella, and at the right is the posterior end of the cell, here covered with pine nut-shaped bacteria, where it actually eats particles of wood.

Dinenympha

“A Ciliate Infusorian, the smallest and most abundant of the three animal parasites, about 1/350-th of an inch in length, is flattened, fusiform, and in motion often twisted. It is longitudinally and, in the twisted condition, spirally striated, and is invested everywhere with fine cilia…The great accumulation of parasites, apparently constantly existing in the White Ant, one of our most common insects, will afford a new and wonderful source of delight to our microscopists.” Leidy 1877. Proc. Acad. Nat. Sci. Philadelphia.

Dinenympha is an Oxymonad protist with eight flagella tightly bound to its body in a series of parallel helixes. It may not swim quickly, but its body pulsates with rapid convulsions due to its motile spine, or axostyle. The axostyle bends in a series of sharp kinks between straight segments that move down the length of the body in angular waves, lending it an unforgettable appearance.