[Plate XXII.] Fig. 29.
Vorticella composita floribus muticis ovalibus, stirpe ramosa. Compound, with naked oval florets, and a branched stem.
These vorticellæ are of a lemon shape, and are generally found in clusters, branching out from a stem, which mostly adheres to some convenient substance.
That species of them which is described by Baker had a very short pedicle, and the animals were much longer than those which are represented at Fig. 29. There was no main stem, but all the pedicles were joined in one center, round which the animals extended themselves as so many radii, forming a very pleasing figure.
The mouths of these animalcula are not ciliated, but they are furnished with a round operculum or cover, connected by a long ligament or muscle, which extends downwards through the body, and is affixed withinside of it, near the tail. This ligament may be contracted or dilated, so that the cover can be removed to some distance from the mouth; in this situation several short hairs maybe found to radiate from it; these have a vibratory motion, by which they excite a current of water, most probably to draw in the proper nourishment, after which they shut or pull down the cover, which they again extend at pleasure: when the cover is pulled close down, the mouth contracts, and no hairs are to be seen.
Fig. 29 represents the vorticella opercularia; ſ, the operculum removed at some distance from the mouth, at t; it is nearly close at r, the mouth contracted, the cover drawn in, and no hairs to be seen; u, a part of the stalk, from which some of the animalcula are separated.
VORTICELLA UMBELLARIA.
[Plate XXII.] Fig. 30.
Vorticella composita, floribus ciliatis globosis muticis, stirpe umbellata. Compound, with ciliated globous naked florets and an umbellated stem.
Vorticella acinosa, simplex, globosa, granis nigricantibus, pedunculo rigido. Müller Animal. Infus. p. 319.