_Amphilep´tus fascíola_ (fig. 29) is furnished with an elongate fusiform or lanceolate flattened body, with a lateral oblique mouth. _Chil´odon cucul´lulus_ (fig. 37) has an oblong thin body, irregularly wavy on the sides; the mouth being situated obliquely in front of the middle, and furnished with a cylinder of parallel rod-like teeth. _Nas´sula el´egans_ (fig. 31) has the body ovoid or oblong, becoming globular when contracted, the mouth being furnished with teeth as in _Chilodon_. It is often found among Oscillatoriæ. URCEOLARÍNA.--_Vorticel´la convallária_ (Pl. XI. fig. 34) is very commonly met with in decomposing infusions. The bell-shaped body is fixed at the end of a slender stalk, which is often seen to be extended and then suddenly contracted into a spiral (fig. 34 _a_). The cilia are arranged around a raised rim at the front of the body, and extend down a fissure leading to the mouth. The sacculi of this infusorium may be readily filled with indigo. The process of longitudinal division may also often be observed, taking about an hour for its completion; and when the new individual is about to separate from the parent, a ring of cilia may be noticed to have sprung up around the base (fig. 36). The encysting process is also often visible, the cilia disappearing, and the body becoming globular and secreting a cyst around it; after a time the contents become resolved into a number of embryos, which escape by the bursting of the cyst (fig. 35). In some cases the _Vorticella_ assumes the form of a _Podoph´rya_ (fig. 40), the surface becoming covered with tentacle-like processes. This _Podophrya_ was formerly considered a distinct species. _Vaginic´ola crystal´lina_ (fig. 33) is contained in a crystalline tube, from which the body can be protruded. The body is of variable form, presenting when fully extended a trumpet shape. The cilia exist at the anterior end, and extend down a lateral fissure as in _Vorticella_. It is found attached to Confervæ in the water of ponds and bog-pools. _Sten´tor polymor´phus_ (fig. 38) is a very beautiful trumpet-shaped infusorium, the body being covered with spiral rows of cilia. The rim is furnished with stouter cilia, its margins at the notch being spirally turned inwards. This infusorium is often found in little groups attached to a gelatinous mass (fig. 38 _c_); and it is met with also in a free or unattached state. COLEP´INA.--_Cóleps hir´tus_ (fig. 32) has a barrel-shaped carapace, transversely and longitudinally furrowed, the furrows being occupied by cilia. It has two or three spines behind, and ten or twelve at the front end of the carapace. It is common among Confervæ, and is very voracious, feeding upon dead Entomostraca, &c.; and if disturbed, at its meal by moving the cover, it will soon return and resume feeding as before.