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Specimen
044
More stentors in this video - an oval one, a bulb-shaped one and even a trumpet shaped one. Stentors are noted for their trumpet-like shape (hence the name stentor, after the Greek herald of the Trojan war). However, when moving, the stentor is contracted into an oval or pear shape. The whole body of the stentor is covered with short hairs or cilia, which are used for locomotion when free swimming. A crown of longer cilia are found at its 'head' and is used to create a current of water from which it sweeps food. Every little while, the stentor will close up the cilia crown and contact, bringing the food within its cell structure. the cell wall envelops the food, and separates to form a round bubble like "vacuole" within the cell. After the nutrition from the food is extracted, this vacuole moves to the outer cell wall and 'pops', evacuating the remaining contents. Since stentors have a cell density higher than the water in which they live, osmotic pressure causes water to transport into the cell. The stentor cell actively collects this excess water into a vacuole, and expels it; thereby maintaining the internal fluid density. They normally eat bacteria and algae, though large stentors are reported to opportunistically eat paramecia, rotifers or anything else that they can catch. |