VORTICELLA BERBERINA.
Vorticella composita, floribus ovalibus muticis, stirpe ramosa. Compound, with oval beardless florets.
This is a species of the vorticellæ, which resembles the preceding one in many respects, particularly in being multiplied in the same manner, that is, by dividing or splitting, according to its length.
They are more slender than the vorticella umbellaria; the branches of the clusters are transparent. When many of them are together, they appear of a changeable violet colour; the clusters are not unlike a sprig of spun glass. The motion of the lips is not so easily distinguished as in the foregoing species, though it may be observed in these whilst they are opening and completing their formation. For at these times the motion is but slow, whereas it becomes afterwards very quick in those that are arrived at a state of perfection.
All the cluster vorticellæ detach themselves from time to time from the stem, and from these they swim about till they fix again upon some convenient substance; the branches, when deserted, bear no more vorticellæ.
VORTICELLA DIGITALIS.
[Plate XXII.] Fig. 31.
Vorticella composita, floribus cylindricis, unisulcatis semiclausis, stirpe ramosa. Compound, with cylindrical florets.
Vorticella composita, cylindrica, crystallina, apice truncata et fissa, pedunculo fistuloso ramosa. Müller Animal. Infus. p. 327.
This species of the vorticella is very scarce, it seems only to have been seen by Rösel, who found it on the monoculus quadricornis, till it was discovered in the year 1784 by Müller, who had sought for it several years before, but in vain.