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Didinium sp. 70 microns long. This single celled creature is a voracious carnivore using special threads (toxicysts) coming from the projection (cytostome) for catching and gulping prey. The beating cilia along the side move it rapidly through the water. Normally there are 2 bands but here there are 4 as the cell is about to divide

Didinium ciliate before division
Stalked suctorian Ephelota
Stalked suctorian Ephelota with tentacles

Ephelota (below) with 2 rotifers caught with tentacles

Stalked Ciliates

Tokophrya sp. 200 microns long. A number of sucking type ciliates are present in the Haven including this beautiful one with constantly moving tentacles that catch and catch prey. Despite needing to attach to a substrate these stalked species become common in the plankton when wind whips up sand or a sudden death of many small crustaceans. 

Another Suctorian species is Ephelota sp, (below) often appearing in samples, sometimes in large numbers. The head is about 70 microns across. 

Stalked ciliateTokophrya, a suctorian feeding with tentacles
Stalked ciliate like a marine Vorticella 

A stalked ciliate like Vorticella 

Dictyocha speculum a silicoflagellid

Dictyocha speculum, a silicoflagellid, 30 microns

The taxonomic group called Radiolaria is complex as there are several similar groups and all are typically lumped together as "Radiolaria". They are a spectacular group of organisms some with a siliceous skeleton of spicules. The single cell is surrounded by a froth and high levels of oil give buoyancy. Most are 100-150 microns.

Radiolaria Acanthometra

A large radiolarian-type species, Acanthometra sp, 240 microns across, very occasionally appears in the Haven but is more of an  open sea species. Note the high levels of oil droplets in the cell. Specimen is damaged where it has been flattened with a glass coverslip under the microscope.

The spicules/spines of this species consist of strontium sulphate and barium. When it dies the spicules dissolve in the seawater while the silica-types species drop to the bottom where the bodies form a sediment. 


A very abundant and diverse group of single celled creatures that secrete a case, called a lorica, in which they live and feed. Made from chitin and protein it may be bowl shaped or like a wine glass. Many of the later are encrusted with mineral and other debris. For such a small organism to construct such complex structures is quite staggering when they are only 50 - 100 microns.

Larger tintinnids, Favela

One of the larger tintinnids, Favela. 200 microns

Eutintinnus ciliate in clear lorica


Clear transparent lorica of a tintinnid

Clear lorica

Lorica of a tintinnid studded with mineral grains x400

Lorica studded with minerals

Eutintinnus ciliate in clear lorica


Tintinnid with protruding cilia
Tintinnid with protruding cilia

Are these two tintinnids exchanging genetic material?

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