The form of the body is elliptical and ventricose, the hind-part somewhat sharp. It is membranaceous, dilatable, winding variously; the hind-part is sometimes replete with darkish molecules. The neck, d, is three or four times longer than the body, of an equal size throughout, except a small degree of thickness at the apex, f, very pellucid. The motion of its neck is very lively, that of the body slow. It is found in water that has been kept for a long time, and which has acquired a vegetable greenness.
81. Vibrio Falx.
V. gibbosus, postice obtusus, collo falcato. A gibbous vibrio, the hind-part obtuse, the neck crooked.
The body is pellucid, elliptical, the fore-part lessening into a little round bright neck, nearly of the same length as the trunk, the hind-part obtuse. The trunk itself is rather rounding or tending to the gibbous, and filled with very small molecules; there are also two bright globules, one within the hind extremity, the other in the middle of the body. The neck being immoveable, the motions of the animalculum somewhat resemble those of a scythe.
82. Vibrio Intermedius.
V. membranaceus, antice attenuatus, postice subacutus. Membranaceous vibrio, the fore-part small, the hinder part somewhat acute.
It seems to be an intermediate species between the preceding vibrio and the fasciola, [No. 74]; it is a thin membrane, constantly folded. The whole of it has a crystalline talky appearance, the middle replete with grey particles of different sizes; it has all round a distinct bright margin; the apex of the neck is truncated, the tail obtuse.
VI. CYCLIDIUM.
Vermis inconspicuus, simplicissimus, pellucidus, complanatus, orbicularis vel ovatus. A simple, invisible, flat, pellucid, orbicular or oval worm.