A pellucid membrane, the fore-part formed into a kind of neck, one edge rising into a protuberance like a hump-back, the other edge convex.
193. Trichoda Proteus.
T. ovalis, postice obtusa, collo elongata retractile, apice crinito. [Plate XXV.] Fig. 56, 57, 58, 59, 60. Oval trichoda, the lower-part obtuse, with a long neck, which it has a power of contracting or extending.
Baker in his Employment for the Microscope, p. 260-266, dignifies this animalculum with the name of proteus, on account of its assuming a great number of different shapes, so as scarce to be known for the same animal in its various transformations; and, indeed, unless it be carefully watched while passing from one shape to another, it will often become suddenly invisible.
When water, wherein any kinds of vegetables have been infused, or animals preserved, has stood quietly for some days or weeks in a glass or other vessel, a slimy substance will be collected about the sides, some of which being taken up with the point of a penknife, placed on a slip of glass in a drop of water, and viewed through the microscope, will, be found to harbour several kinds of little animals that are seldom seen swimming about at large. The insect we are treating of is one of these, and was discovered in such slime-like matter taken from the side of a glass jar, in which small fishes, water-snails, and other creatures had been kept. Its body in substance and colour resembled that of a snail; the shape thereof was somewhat elliptical, but pointed at one end, whilst from the other proceeded a long, slender, and finely proportioned neck, terminated with a head, of a size perfectly suitable to the other parts of the animal.
194. Trichoda Versatilis.
T. oblonga, postice acuminata, collo retractili, infra apicem crinito. Oblong trichoda, the hind-part acute, with a neck that it can extend or contract at pleasure, the under-part of the extremity of the neck hairy.
It resembles in some measure the trichoda proteus just described, but the neck is shorter, the apex less spherical, and the hinder part of the trunk acute. It lives in the sea.
195. Trichoda Gibba.
T. oblonga, dorso gibbera, ventre excavata, antice ciliata, extremitatibus obtusis. [Plate XXV.] Fig. 55. Oblong trichoda, with a bunch on the back, the belly hollowed out, the fore-part ciliated, both ends obtuse.