"The Foraminifera are enclosed in minute calcareous shells, early invisible to the naked eye; they are found among the sands of the sea. The, in common with corals, are great agents in helping to form islands, which rise out of the bosom of the deep in the warm regions of the globe."

Alveolina Ovoidea (d'Orbigny)

"The Foraminifera are enclosed in minute calcareous shells, early invisible to the naked eye; they are…

"These little creatures frequently have the appearance of small, rounded masses, like drops of water. They are naked, without any apparent organization."

Amoeba Princeps (Ehrenberg)

"These little creatures frequently have the appearance of small, rounded masses, like drops of water.…

"The Foraminifera are enclosed in minute calcareous shells, early invisible to the naked eye; they are found among the sands of the sea. The, in common with corals, are great agents in helping to form islands, which rise out of the bosom of the deep in the warm regions of the globe."

Calcarina Calcitrpoides (Lamarck)

"The Foraminifera are enclosed in minute calcareous shells, early invisible to the naked eye; they are…

"The shell advances beyond this simple type by a process of linear budding, the first cell being spherical, with an opening through which a second segment is formed, generally a little larger than the first. This new growth is followed by others developed in the same way, until the organism attains its maturity."

Dentalina Subarcuata

"The shell advances beyond this simple type by a process of linear budding, the first cell being spherical,…

"This is the most common species of the <em>Euglenia</em>, and is among the most widely diffused of all the Infusioria. It is this animalcule which is often met with covering stagnant pools with a floating surface of green."

Euglena Viridis

"This is the most common species of the Euglenia, and is among the most widely diffused of…

"The Foraminifera are enclosed in minute calcareous shells, early invisible to the naked eye; they are found among the sands of the sea. The, in common with corals, are great agents in helping to form islands, which rise out of the bosom of the deep in the warm regions of the globe."

Fabularia Discolithus (Defrance)

"The Foraminifera are enclosed in minute calcareous shells, early invisible to the naked eye; they are…

Related to the Paramecians. These are remarkable for their size and voracity; they sometimes attain the length of a twelfth of an inch.

Kondylostoma Patens

Related to the Paramecians. These are remarkable for their size and voracity; they sometimes attain…

"The Monads are infusorial animalcules which make an early appearance in vegetable infusions. They have no skin; the substance of their bodies can shorten itself or draw itself out more or less; their organization is extremely simple."

Monas Lens

"The Monads are infusorial animalcules which make an early appearance in vegetable infusions. They have…

In this image, (a) represents the parasites in the various stages of development, and (b), the larger animalcule on which they have established themselves.

Paramecium Aurelia and its Parasites

In this image, (a) represents the parasites in the various stages of development, and (b), the larger…

"Paramecium Bursaria is the only species of Paramecium that forms symbiotic relationships with algae, and are often used in biology classrooms as examples of protozoans, and as examples of symbiosis."

Paramecium Bursaria (Pritchard)

"Paramecium Bursaria is the only species of Paramecium that forms symbiotic relationships with algae,…

"The singular phenomenon of spontaneous division may be witnessed by any one having patience to examine the creature long enough under the microscope, isolated from its innumerable companions. This process is represented here, A and B being the adult, C the same in course of separation, D after its completion."

Propagation of an Infusorian by Spontaneous Division

"The singular phenomenon of spontaneous division may be witnessed by any one having patience to examine…

"The common Volvox is found in great abundance during the summer, and even in the depth of winter in lakes and ponds of fresh water."

Volvox Globular

"The common Volvox is found in great abundance during the summer, and even in the depth of winter in…

"The common Volvox is found in great abundance during the summer, and even in the depth of winter in lakes and ponds of fresh water."

Volvox Globular

"The common Volvox is found in great abundance during the summer, and even in the depth of winter in…