Tardigrades (also known as water bears) are microscopic, 8-legged animals comprising the phylum Tardigrada. Water bears can withstand temperature extremeties, high radiation, and even the vacuum of space, making them one of the most durable organisms on the planet aside from extremophilic archaea.


Closterium is a genus of Desmids (order, Desmidiales). Desmids are characterized by their unique, delecate, and  symmetrical cell walls, composed of cellulose.

Centric Diatom

In a sample of saltwater, I discovered this centric diatom. There are two basic morphological types of diatoms: Pennate (rods), and Centric (round). All of the diatoms previously mentioned on this blog were pennate forms.


Coleps is a genus of ciliates. They are characterized by the presence of a biomineralized test of calcium carbonate, or chalk, in which the cell resides. At one end is a small aperture from which the cell may feed. Coleps are viscous predators, often latching onto their prey and ripping of chunks of tissue or cytoplasm. To make matters worse, Coleps  are often found in swarms. These cells are around 50 micrometers in size.


Cyclidium is a small, energetic ciliate covered in many long cilia. Its pellicle is slightly ridged, and it possesses and cytostome on the central side of the cell. Surrounding the cytostome are a few oral cilia and an undulating membrane. At least 15 Cyclidium can be seen in this photo. Cyclidium cells can grow to around 30 – 40 micrometers.


Difflugia Acuminata

Difflugia Acuminata is a species of testate amoebae. Its test, or shell, is xenogenic, meaning that the amoeba captured and agglutinated hard materials together, sometimes including empty diatom frustules or maybe live diatoms.

Visible extending up to the top left corner of the photo are a few lobose ectoplasmic pseudopodia.


Euglena has a stiff cell membrane known as a pellicle, which can be seen easily in these two photos. Euglena’a pellicle is composed of protein strips that wrap around the cell. Towards the left side of the cell in the featured photo is a single red eyespot. Around the middle of the cell is an elongated ring-like structure called a paramylon. The paramylon was briefly mentioned in an earlier post regarding Phacus.

Continue reading “Euglena”


Trachelomonas is a genus within Euglenaceae, a family including Euglena. Trachelomonas differs from most other Euglenids as it possesses a shell-like structure called a lorica. This lorica contains ferric hydroxide, which gives it a redish coloring. At one end of the lorica is a small aperture from which the cell’s flagellum may emerge. Small spines are also present outside the lorica.

A relatively long flagellum can be seen extended from the green cell (left).

Continue reading “Trachelomonas”


Here we see Euglenoid cells in a dormant stage of their life cycle known as palmella. Each green cell is contained within a gelatinous mucilage. A few cells can be seen dividing.