We now come to another division of these animals, to which later writers have given the name of vorticellæ; this term I shall therefore adopt, being of opinion that it behoves every man to maintain that order in scientific arrangement which is not inconsistent with truth, except he can produce another arrangement more expressive of the nature of the objects it is designed to discriminate; a process requiring no small degree of attention.
The variety that may be observed in these minute animals confirms a principle, which, the more it is inquired into, the more it will be found to accord with the general operations in nature, namely, that there is always a pre-existent principle of life necessary to the organization both of animals and vegetables; that the alimentary and other particles which are added to, or apparently belong to them, produce nothing of themselves; they are incapable of forming the least fibre, but they are able to become constituent parts of one organical whole, together with the instruments whereby the forming principle is manifested, and rendered capable of acting upon certain orders of creatures.
VORTICELLA.
Animal calyce vasculoso; ore contractili ciliato, terminali. Stirps fixa.
A small animal, with a vascular cup; the mouth is at one end ciliated, and capable of being contracted, the stem fixed.
VORTICELLA ANASTATICA.
[Plate XXI.] Fig. 13, 14, 15, and 16*.
Vorticella anastatica, composita, floribus campanulatis, stirpe multiflora rigescente.
Vorticella anastatica, compound, with bell-shaped flowers, and a rigid stem.
Cluster polype, second species. Trembley, Philos. Trans. vol. xliv. part. 2. p. 643.