V. oblongus, utroque fine attenuatus, collo cauda longiore. Oblong vibrio, both ends attenuated, the neck longer than the tail.
The trunk is oblong, opake, and filled with molecules. Both the fore and the hind-part is prolonged into a pellucid talky membrane, which the animalculum has a power of retracting at pleasure. The tail is more acute than the neck. It is most generally found in salt water; a species of them have been found in river water, with a longer neck.
78. Vibrio Cygnus.
V. ventricosus, collo adunco. Corpulent vibrio, with a crooked neck.
This animalculum is little more than a most pellucid line, crooked at top, prominent in the middle, and sharp at the end; the fore-part, or neck, is equal in length to the rest of the body, and three times longer than the hind-part or tail; the intermediate part swelling out, is full of dark-coloured molecules and pellucid intestines. It is very small, and the most slothful of all those which move and advance their necks.
79. Vibrio Anser.
V. ellipticus, collo longo, tuberculo dorsali. [Plate XXV.] Fig. 27 and 29. Elliptical vibrio, with a long neck, and a little lump on the back.
It is between the vibrio proteus and vibrio falx, and is distinguished by the lump b, Fig. 29, on the back, placed behind the neck; from this an even long neck, a, proceeds. The trunk, d, is elliptic, round, and without any lateral inequality; full of molecules, the hind-part, e, sharp and bright, the fore-part produced into a bending neck that is longer than the body; the apex even and whole, with blue canals passing between the marginal edges, occupying the whole length of the neck; in one of them a vehement descent of water to the beginning of the trunk is perceivable. The motion of the body is slow, that of the neck is more lively and flexuous, sometimes spiral. It is found in water where duck-weed grows.
80. Vibrio Olor.
V. ellipticus, collo longissimo, apice nodoso. [Plate XXV.] Fig. 28. Elliptical, with a very long neck, and a knob on the apex.