This is one of the larger species, the margin is pellucid, and the inner part contains a great number of black molecules.
VII. PARAMÆCIUM.
Vermis inconspicuus, simplex, pellucidus, membranaceus, oblongus. An invisible, simple, membranaceous, flat, and pellucid worm.
93. Paramæcium Aurelia. Volvox Terebella. Ellis.
P. compressum, versus anticem plicatum, postice acutum. Compressed paramæcium, oblong, folded towards the fore-part, the hinder-part acute.
This is rather a large animalculum, membranaceous, pellucid, and four times longer than it is broad; the fore-part obtuse, transparent, without intestines; the hind-part replete with molecules of various sizes; the fold, which goes from the middle to the apex is a striking characteristic of the species, forming a kind of triangular aperture, and giving it somewhat the appearance of a gimblet. Its motion is rectilinear, reeling or staggering, and generally vehement.
They are frequently found cohering lengthwise; the lateral edges of both bodies appear bright. They may also sometimes be seen lying on one another alternately, at others, adhering by the middle. They will live many months in the same water without its being renewed. They are to be found in June in ditches where there is plenty of duck-weed.
94. Paramæcium Chrysalis.
P. cylindraceum, versus anticam plicatum, postice obtusum. [Plate XXV.] Fig. 26. Cylindrical paramæcium, folded towards the fore-part, the hinder-part obtuse.
It differs very little from the preceding, only the ends, a b, are more obtuse, and the margins filled with black globules. It is an inhabitant of salt water.