Returning to the organization of the little creature which occupies the cell, it is found that the upper and retractile portion, which is of extreme delicacy, terminates anteriorly in a circle of long tentacles, in the centre of which is the mouth. These tentacles are fringed laterally by a series of vibratile cilia. "When the animal displays itself," says Frédol, "this circle of microscopic threads of extreme tenuity first show themselves rising from the summit of the cell; this is followed by the upper part of its body, which is more or less flexible; the tentacles follow between the threads, pushing them on one side." These tentacles are furnished on the back with a dozen appendages like very fine hairs, attached to them nearly at right angles, in addition to the lateral cilia already spoken of, which play a very important part in the arrangements of most microscopic animals. At the moment when the tentacles appear outside the cell, the tunic of the animalcule, which has the power of expanding or contracting itself, is gradually unrolled. It soon spreads out its pretty little arms, the appendages and cilia beginning their rapid vibrations, until the eye, deceived by the rapidity and regularity of their movements, is dazzled, and the beholder begins to think that he sees rosy drops of dew waving to and fro, twisting and untwisting themselves. The corpuscles which float round the animal are violently agitated, as if they were under the influence of some strong breeze. Unhappy, indeed, is the fate of the unfortunate infusoria which chance leads at this moment into the fatal circle. In many species, observers have discovered a special organ called the _vibracule_, which deserves our attention for a moment. It is a hollow filament, situated at the upper and outer angle of each cell, filled with a substance which is at once fibrous and contractile, admitting of some very remarkable movements, which occur regularly, and generally at very short intervals. At first the filament inclines itself towards the base, trembles, oscillates, and seems to sink; presently it recovers itself, and inclines in the opposite direction, where it repeats the same operation with the same order and in the same time. "What are the functions thus performed?" asks Frédol. "Are they, we would ask, independent up to a certain point of the will of the Bryozoaire? What is their purpose?" We think he answers, "That this organ serves the purpose of cleansing, and especially that of strengthening, the entrance to the cell. It even continues its movement after the animal has been mutilated or killed. The poor sickly or dead creature continues to be defended by its protecting vibracule." The prey which is drawn into the vortex by the tentacles and their appendages enters into the mouth, to which is attached a pharynx, oesophagus, stomach, and intestines. In the back or hæmal region, not far from the mouth, there is a special opening for this intestine.