V. caudata, cylindracea, mutica, cauda spinis duabus longis terminata. With a tail, cylindrical, beardless, the tail terminating in two long spines.
The body is large, the apex of an equal thickness, obtuse, with rotatory filaments; the tail acute, with two pellucid spines, in length about one-third part of the body, alternately separating from and approaching each other.
328. Vorticella Stentorea.
V. caudata, elongata, tubæformis limbo ciliato. Long-tailed vorticella, trumpet-shaped, the arms furnished with rows of short hairs. See this fully described by the name of hydra stentorea, in [page 392].
329. Vorticella Socialis.
V. caudata, aggregata, clavata; disco obliquo. A description of this vorticella has also been given, as hydra socialis, in [page 395].
330. Vorticella Flosculosa.
V. caudata, aggregata, oblongo-ovata, disco dilatato pellucido. [Plate XXVII.] Fig. 51 and 52. With a tail aggregated, of an oblong oval shape, with a dilated pellucid disc.
To the naked eye it appears as a yellow globule, adhering to the ceratophyllum, or common horn-wort, Fig. 52, a, like a little flower; or a heap of yellow eggs, b. With the assistance of the microscope they are discovered to be a congeries of vorticellæ, constituting a sphere from a mouldy center. They contract or extend their bodies either when alone or associated, and excite a vortex in the water by means of the disc. When they quit the society, and act singly, their parts may be more readily distinguished, and will be found to consist of a head, abdomen, and tail. The head is often drawn back so far into the abdomen, that it cannot be seen, exhibiting only a projecting, broad kidney-shaped disc. The abdomen, Fig. 51, d, is oblong, oval, and pellucid, replete with obscure intestines, amongst which are one or two remarkable black oval spots, e; the tail, f, is sharp, twice as long as the abdomen, either rough and annulated, or altogether smooth.