Chapter XIII: Trichoda

Vermis inconspicuus, pellucidus, crinitus. An invisible, pellucid, hairy worm.

172. TRICHODA GRANDINELLA. T. sphærica, pellucida, superne crinata. Spherical, pellucid, the upper-part hairy.

A most minute pellucid globule, the intestines scarce visible, the top of its surface furnished with several short bristles, which are not easily distinguished, as the animalculum has a power of extending and withdrawing them in an instant. It is found in pure water, and in infusions of vegetables.

173. TRICHODA COMETA. T. sphærica, antice crinita, globulo appendente. Plate XXV. Fig. 46 and 47. Spherical, the fore-part hairy, with an appendant globule.

It is a pellucid globule, replete with bright intestines, the fore-part furnished with hairs, the hind-part with a pellucid appendant globule.

174. TRICHODA GRANATA. T. sphærica, centro opaco peripheria crinita. Plate XXV. Fig. 48. Spherical, with an opake center, the periphery hairy.

It resembles the trichoda grandinella and trichoda cometa just described. It has a darkish nucleus in the center; its intestines are imperceptible; short hairs on the edge.

175. TRICHODA TROCHUS. T. subpiriformis, pellucida, antice utrinque crinita. Trichoda somewhat of a pear-shape, pellucid, each side of the fore-part distinguished by a little bunch of hairs.

176. TRICHODA GYRINUS. T. ovalis, teres, crystallina, antice crinita. Oval, round, crystalline trichoda, the front hairy.

It is one of the smallest among the trichoda, the body smooth and free from hairs, except at the fore-part, where there are a few. It is found in salt water.

177. TRICHODA SOL. T. globularis, undique radiata. Plate XXV. Fig. 65 and 66. Globular trichoda, everywhere radiated.

This splendid creature constitutes a new genus, but as we know of no more of the same kind, it is introduced here. It is a little crystalline round corpuscle, the upper part convex; it is beset with innumerable diverging rays, which are longer than the diameter of the body, proceeding from every part of its surface: the inside is full of molecules. The body contracts and dilates, but the animalculum remains confined to the same spot. It was found with other animalcula in water which had been kept for three weeks. It propagates by division, and is represented as dividing in Fig. 66.

178. TRICHODA SOLARIS. T. sphæroidea, peripheria crinita. Spheroidal trichoda, with a few hairs round the circumference.

The body is orbicular, bright, and filled with globular intestines; in many, a moveable substance, something like the letter S, may be discovered; it has hairs, seldom exceeding seventeen in number, which are disposed round the circumference, each of them nearly equal in length to the diameter of the animalculum.

179. TRICHODA BOMBA. T. mutabilis, antice pilis sparsis. Plate XXV. Fig. 67 and 68. Changeable, with a few hairs dispersed on the fore-part.

It is a thick animalculum, larger than the trichoda granata, No. 174, and of a yellow colour; pellucid, and replete with clay-like molecules; it is very lively, moving about with so much velocity, as to elude the sharpest sight and most pertinacious observer, and assuming various shapes, sometimes appearing spherical, sometimes reniform, or kidney-shaped, sometimes as at Fig. 67.

180. TRICHODA ORBIS. T. orbicularis, antice emarginata crinita. Orbicular, the fore-part notched and hairy.

It in some, respects resembles the former, but is larger. It is composed of vesicular molecules; is of a spherical figure, smooth, pellucid, and a little notched in the fore-part. The notched part is filled with long hairs, but there are none on the rest of the body.

181. TRICHODA URNULA. T. urceolaris, antice crinita. Plate XXV. Fig. 64. This trichoda is in the form of a water pitcher, the fore-part hairy.

A membranaceous pellucid animalculum, the hind-part obtuse, the middle something broader, the fore-part truncated, filled with vesicular black molecules; the hairs in the fore-part are even and short. Its motion is slow.

182. TRICHODA DIOTA. T. urceolaris, antice angustata, ora apicis utrinque crinita. Pitcher-shaped trichoda, the fore-part smallest; the upper part of the mouth hairy at the edges.

The body is of a clay-colour, and filled with molecules; the upper-part cylindrical and truncated, the lower part spherical.

183. TRICHODA HORRIDA. T. subconica antice latiuscula, truncata postice obtusa, setis radiantibus cincta. Trichoda somewhat of a conical form, the fore-part rather broad and truncated, the lower-part obtuse, and the whole covered with radiating bristles.

184. TRICHODA URINARIUM. T. ovata, rostro brevissimo crinito. Egg-shaped, with a short hairy beak.

185. TRICHODA SEMILUNA. T. Semiorbicularis, antice subtus crinita. Semiorbicular, the fore-part hairy underneath.

A smooth pellucid animalculum, and shaped like a crescent.

186. TRICHODA TRIGONA. T. convexa, antice ciliata, postice erosa. Plate XXV. Fig. 63. Convex, the fore-part ciliated, the hind-part as it were gnawed off.

This is a triangular animalculum, a little convex on both sides, the fore-part acute, the hind-part a little broader. A notch is seen at _a_, in the hind-part; _b_, the ciliated fore-part; _c_, a tube.

187. TRICHODA TINEA. T. clavata, antice crinita, postice grossa. This is clubbed, the fore-part hairy, the hind-part large.

This animalculum is round, not very pellucid, narrow in the fore-part, and resembling an inverted club; it is also like some of the tinea.

188. TRICHODA NIGRA. T. ovalis compressa, antice latior crinita. Oval, compressed trichoda, the fore-part broader and hairy.

The body is opake, when in violent motion it is black, when at rest one side is pellucid; the middle of the fore-part is furnished with little moveable hairs. It was found in salt water.

189. TRICHODA PUBES. T. ovato-oblonga gibba, antice depressa. Plate XXV. Fig. 61 and 62. An egg-shaped oblong bunch, the fore-part depressed.

An animalculum with a bunch above the hind-part, marked with black spots, depressed towards the top, a little folded, and somewhat convex underneath; at least this is its appearance when in motion. Very minute hairs occupy the apex, but they are seldom visible till the creature is in the agonies of death, when it extends and moves them vehemently from an arched chink at top, apparently endeavouring to draw in the last drop of water. It is found in water where the duck-weed grows, chiefly in December. _b_, the hairs; _c_, the black globules; _a_, the projecting bunch.

190. TRICHODA FLOCCUS. T. membranacea, antice subconica, papillis tribus crinitis. Membranaceous trichoda, the fore-part rather conical; three small papillæ project from the base, which are set with hairs.

191. TRICHODA SINUATA. T. oblonga depressa, altero margine sinuato crinita, postice obtusa. An oblong depressed trichoda, one margin hollow and hairy, the lower end obtuse.

The intestines seem to be more lymphatic than molecular; it is of a yellow colour, and the hollow edge ciliated. It was found in river water.

192. TRICHODA PRÆCEPS. T. membranacea, sublunata, medio protuberante, extorsum crinita. Membranaceous trichoda, somewhat lunated, protuberant in the middle, a row of hairs on the outside.

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.

The body is pellucid, the upper part swelled out, within it are numerous obscure molecules, and three large globules, the ends rather incline downwards; when the water begins to fail, a few minute hairs may be discovered about the head and at the abdomen; the body then becomes striated longitudinally.

196. TRICHODA FOETA. T. oblonga, dorso protuberante, antice ciliata, extremitatibus obtusis. Oblong trichoda, with the back protuberant, the fore-part ciliated, both ends obtuse.

The body is round and long, and when extended somewhat resembles a rolling-pin in shape; both ends are obtuse, and one shorter than the other; it can draw in the ends and swell out the sides, so as to appear almost spherical.

197. TRICHODA PATENS. T. elongata, teres, antice foveata, fovæ marginibus ciliata. Plate XXV. Fig. 54. This trichoda is long, round, in the fore-part it has a long hole, the edges of which are ciliated.

It is a long cylindrical animalculum, filled with molecules; the fore-part bright and clear, with a long opening, _a_, near the top, which tapers to a point, and is beset with hairs. It is found of different lengths in salt water.

198. TRICHODA PATULA. T. ventricosa, subovata, antice canaliculata, apice et caniculo crinito. Big-bellied, rather inclining towards an oval figure, with a small tube at the fore-part, the upper-end of which is covered with hairs.

199. TRICHODA FOVEATA. T. oblonga, latiuscula, antice corniculis micantibus, postice mutica. Oblong trichoda, rather broad, three little horns on the fore-part, the hinder-part beardless.

200. TRICHODA STRIATA. T. oblonga, altero margine cursum, sinuata et ciliata, utraque extremitate obtusa. Oblong trichoda, one edge rather curved, and also furnished with a row of hairs; both extremities obtuse.

It is a splendid animalculum, of a fox colour, and at first sight might be taken for a kolpoda. The body is oblong, the lower end somewhat larger than the other, the body becoming smaller at that part where the hairs commence; it has a set of streaks which run from one end to the other, and at the abdomen a double row of little eggs, lying in a transverse direction. It was found in river water in December.

201. TRICHODA UVULA. T. planiuscula elongata, æqualis, antice crinita. Plate XXV. Fig. 53. Rather flat and long, of an equal size throughout, the fore-part hairy.

This animalculum is six times longer than broad, round, flexuous, and of an equal size; the greater part filled with obscure molecules; the fore-part, _a_, rather empty, distinguished by an alimentary canal, and lucid globules near the middle, _c_; short hairs occupy the margin of the fore-part, some are dispersed into a chink near the canal. It is found in an infusion of hay and other vegetables.

202. TRICHODA AURANTIA. T. subsinuata, ovata, antice patula, apice ad medium crinita. Trichoda somewhat sinuated, oval, the fore-part broad, the apex hairy to the middle.

It is of a gold colour, pellucid, and filled with a variety of vesicles.

203. TRICHODA IGNITA. T. ovata, apice acuminata, subtus fulcata, fulco crinito. Oval trichoda, the apex rather acute, the under-part furrowed, the furrows hairy.

It is of a fine purple gold colour, somewhat of a reddish cast, pellucid, splendid, with a number of globules of different sizes; the fore-part small, the hind-part obtuse, and having a very large opening, which appears to run through the body.

204. TRICHODA PRISMA. T. ovata, subtus convexa, supra in carinam compressa, antice angustior. Oval trichoda, the under part convex, the upper part compressed into a kind of keel, the fore-part small.

It is very small, and so transparent that it cannot easily be delineated; its form is singular, and no hairs can be observed.

205. TRICHODA FORCEPS. T. ovalis, antice forcipata, cruribus inæqualibus crinitis. Oval trichoda, with a pair of forceps at the fore-part, with unequal hairy legs.

A large animalculum, somewhat depressed, of a pellucid yellow colour, and filled with molecules; in the lower part there is a black opake globule, the fore-part is divided into long lobes, one of which is falciform and acute, the other dilated, and obliquely truncated; both the apex and the edge of these are furnished with hairs of different lengths; it can open, shut, or cross these lobes at pleasure; by this motion of them it appears to suck in the water. It was found about the winter solstice in water, covered with lemnæ.

206. TRICHODA FORFEX. T. ventrosa, antice forcipata, postice papilla duplici instructa. Round and prominent trichoda, the fore-part formed into a kind of forceps, and two small protuberances.

One of the forceps of this animalculum is twice as long as the other, hooked, and ciliated. It was found in river water.

207. TRICHODA INDEX. T. obovata, margine antico subtus crinito, alteroque apicis in degitum producto. Obovated trichoda, the under part of the front of the margin hairy, the apex is formed by the fore-part, projecting like the finger on a direction-post. It was found in salt water.

208. TRICHODA S. T. striata, antice ciliata, extremitatibus in oppositum flexis. Striated trichoda, the fore part ciliated, the extremities bent in opposite directions.

A yellow animalculum, formed of two pellucid membranes, striated longitudinally; the lower end is obliquely truncated.

209. TRICHODA NAVICULA. T. triquetra, antice truncata ciliata, postice acuta prominula. Three-cornered trichoda, the fore-part truncated and ciliated, the hind-part acute, and bent a little upwards.

It has a crystalline appearance, rather broad, the under side towards the hinder-part convex, the fore-part broad, the apex nearly a straight line, the bent end pointed and turned upwards; and a kind of longitudinal keel running down the middle.

210. TRICHODA SUCCISA. T. ovalis depressa, margine crinito, postice in crura inæqualia erosa. Flattened oval trichoda, the edge hairy, the hinder part hollowed out so as to form two unequal legs.

211. TRICHODA SULCATA. T. ovato-ventricosa, apice acuminata, fulco ventrali, utrinque crinito. Ovated ventricose trichoda, the apex acute, with a furrow at the abdomen, and both sides of it ciliated.

212. TRICHODA ANAS. T. elongata, apice colli subtus crinito. Plate XXV. Fig. 49. Long, the apex of the neck underneath hairy.

A smooth animalculum, five times broader than it is long, filled with darkish molecules; it has a bright neck, _b c_; under the top of the neck at _d_ a few unequal hairs are perceptible. Its motions are languid. It is found in pure water.

213. TRICHODA BARBATA. T. elongata, teres, subtus ab apice ad medium crinita. Long trichoda, round, the under part from the apex to the middle hairy.

This animalculum is round, somewhat linear, with both ends obtuse; the fore-part narrower, forming as it were a kind of neck, under which is a row of fluctuating hairs. The trunk is full of grey molecules.

214. TRICHODA FARCIMEN. T. elongata, torulosa, setulis cincta. Plate XXV. Fig. 50 and 52. Long and thick trichoda, surrounded with small bristles.

The body is long, round, pellucid, and covered with very minute hairs; it has also a great number of mucid vesicles about the body.

215. TRICHODA CRINITA. T. elongata, teres, undique ciliata, subtus ad medium usque crinita. Long trichoda, round, everywhere ciliated on the upper part, and the under part likewise hairy as far as the middle.

216. TRICHODA ANGULUS. T. angulata, apice crinita. Angular, the apex hairy.

This animalculum is long, more convex than most of the genus, divided by a kind of articulation into two parts equal in breadth, but of different lengths, the fore-part being shorter than the hind-part; the apex furnished with short waving hair, indistinct molecules withinside, no hair on the hind-part.

217. TRICHODA LINTER. T. ovato oblonga, utraque extremitate prominula. Plate XXV. Fig. 51. The shape of an oblong egg, with prominences at both extremities.

Both extremities of the body are raised, so that the bottom becomes convex, and the upper part depressed like a boat. It varies in shape at different ages, and sometimes has a rotatory motion. It is found in an infusion of old grass.

218. TRICHODA PAXILLUS. T. linearis depressa, antice truncata crinitaque, postice obtusa. Linear flat trichoda, the fore-part truncated and hairy, the hinder-part obtuse.

A long animalculum, full of grey molecules; the fore-part rather smaller than the hind-part, and furnished with minute hairs. It was found in salt water.

219. TRICHODA VERMICULARIS. T. elongata, cylindracea, collo brevi, apice crinito. Plate XXVII. Fig. 1. Long cylindrical trichoda, with a short neck, the apex hairy.

Gelatinous, the fore-part pellucid, the hind-part full of molecules. It was found in river water. It is represented in different appearances in the figure; _a_, the neck; _b_, the hairs; _c_, a little vesicle in the hinder-part.

220. TRICHODA MELITŒA. T. oblonga, ciliata, colli dilatabilis, apice globoso, pilifero. Plate XXVII. Fig. 3. Oblong ciliated trichoda, with a dilatable neck, the apex globular, and surrounded with hairs, the edge is ciliated, and a kind of peristaltic motion perceivable in it. It is found, in salt water, though but very rarely. _a_, the neck; _b_, the globular apex; _c_, the body ciliated.

221. TRICHODA FIMBRIATA. T. obovata, apice crinita, postice oblique truncata, serrata. Plate XXVII. Fig. 2. Obovated trichoda, the apex hairy, the hinder-part obliquely truncated and serrated.

222. TRICHODA CAMELUS. T. antice crinita, crassiuscula medio utrinque emarginata. Thick, and the fore-part hairy, with notches on the middle and each side.

The fore-part of the body is ventricose; the back divided by an incision in the middle into two tubercles; the lower part of the belly sinuated; its motions are languid. It is found, though not often, in vegetable infusions.

223. TRICHODA AUGUR. T. oblonga, vertice truncata, antico corporis margine, superne pedata, inferne setosa. The body is oblong, depressed, pellucid, and filled with molecules; the vertex truncated, the fore-part forming a small beak; underneath are three feet; beyond these, towards the hinder-part, it is furnished with bristles.

224. TRICHODA PUPA. T. cucullata, fronte crinita, cauda inflexa, This trichoda is hooded, the front hairy, the tail inflected.

The body is rather round, pellucid and consists of three parts; the head, which is broad, appears to be hooded, the top being furnished with very small hairs; a transparent vesicle occupies the lower region of the head; and over the breast from the base of the head is suspended a production resembling the sheath of the feet in the pupa of the gnat.

225. TRICHODA LUNARIS. T. arcuata, teres, apice crinita, cirro, caudali inflexo. Arched trichoda, round, the apex hairy, the tail bent.

This animalculum is round and crystalline; the hind-part somewhat smaller than the fore-part; the intestines are with difficulty distinguished. The edge of the back and the part near the tail are bright and clear. It bends itself into the form of an arch.

226. TRICHODA BILUNIS. T. arcuata, depressa, apice crinita, cauda biseta. Arched flattened trichoda, the apex hairy, and two little bristles proceeding from the tail.

227. TRICHODA RATTUS. T. oblonga, carinata, antice crinita, postice seta longissima. Plate XXVII. Fig. 4. Oblong trichoda, with a kind of keel; the fore-part hairy, and a very long bristle proceeding from the hinder-part. _a_, the mouth; _b_, a small knob at the bending of the tail; _c_, the tail.

228. TRICHODA TIGRIS. T. subcylindrica, elongata, apice crinita, cauda setis duabus longis. This trichoda is long, and somewhat cylindrical, the apex hairy, the tail divided into two long bristles.

It resembles the former, but differs in the form of the tail, which consists of two bristles, and likewise in having a kind of incision in the body, at some little distance from the apex.

229. TRICHODA POCILLUM. T. oblonga, antice truncata, crinita, cauda articulata, biseta. Plate XXVII. Fig. 5 and 6. Oblong trichoda, the fore-part truncated and hairy, the tail articulated, and divided into two bristles.

The body is cylindrical, pellucid, muscular, and capable of being folded up; it appears double; the interior part is full of molecules, with an orbicular muscular appendage which it can open and shut, and this forms the mouth. The external part is membranaceous, pellucid, dilated, and marked with transverse streaks; the animalculum can protrude or withdraw the orbicular membrane at pleasure. Some have four articulations in the tail, others five; and it has two pair of bristles, or projecting parts, one placed at the second joint, the other at the last. It has been frequently found in marshes. In Fig. 6 it is seen with the mouth open; in Fig. 5, with it shut, _a a_, the jaws; _b b_, the first bristles; _c c_, the second pair; _d_, the spine at the tail.

230. TRICHODA CLAVUS. T. antice rotundata, crinita, postice acuminato-caudata. The fore-part round and hairy, the hind-part furnished with a sharp tail. This animalculum has a considerable resemblance to a common nail.

231. TRICHODA CORNUTA. T. supra convexa, subtus plana, apice crinita, cauda lineari simplici. Trichoda with the upper part convex, the under side plain, the apex hairy, the tail linear and simple.

To these characters we may add, that the body is membranaceous, elliptical, closely filled with molecules; the fore-part lunated, the hinder-part round, and terminating in a tail as long as the body.

232. TRICHODA GALLINA. T. elongata, antice sinuata, fronte crinita, cauda pilosa. Long trichoda, the fore-part sinuated, the front hairy, the tail formed of small hairs.

It is of a grey colour, flat, with seven large molecules and globules within it, the front obtuse, and set with hairs; the hinder-part terminating in a tail formed of very fine hairs. It was found in river water.

233. TRICHODA MUSCULUS. T. ovalis, antice crinita, postice subtus caudata. Plate XXVII. Fig. 7. Egg-shaped, the fore-part hairy, the tail projecting from the under part.

A smooth egg-shaped animalculum, with a double margin or line drawn underneath it; the fore-part narrow, and furnished with short hairs, which are continually playing about; underneath the hind-part is a small tail. It has molecular intestines, and moves slowly. It is found in infusions of hay which have been kept for some months, _a_, the head; _b_, the tail.

234. TRICHODA DELPHIS. T. clavata, fronte crinita, cauda acuminata, subreflexa. Clubbed trichoda, the front hairy, the tail small and rather bent upwards.

It is smooth and pellucid, having the fore-part dilated into a semicircle, gradually decreasing in breadth towards the tail; the front is hairy, the hairs standing as rays from the semicircular edge; one of these edges is sometimes contracted. It is to be found in river water.

235. TRICHODA DELPHINUS. T. oblonga, antice crinita, postice cauda reflexa truncata. Plate XXVII. Fig. 8. Oblong, the fore-part hairy; in the hind-part is the tail, which is turned back, the end of it truncated.

A pellucid, smooth, egg-shaped animalculum; the hind-part terminating in a tail about half the length of the body, dilated at the upper end, truncated, and always bent upwards.

In the inside are vesicles of an unequal size; it moves sometimes on its belly, sometimes on its side; the tail seldom varies its position. It was found in hay which had been infused for some months, _a_, the hairs on the fore-part; _b_, the tail.

236. TRICHODA CLAVA. T. clavata, fronte crinita, cauda reflexili. Club trichoda, the fore-part hairy, the tail turned back.

The fore-part is thick, the hind-part narrow; both extremities obtuse, pellucid, and replete with molecules; the hind-part bent down towards the middle.

237. TRICHODA CUNICULUS. T. oblonga, antice crinita, postice subacuminata. Oblong, the fore-part hairy, the hind-part rather acute, filled with molecules and black vesicles.

238. TRICHODA FELIS. T. curvata, grossa, antice angustior, postice in caudam attenuata, subtus longitudinaliter crinita. Plate XXVII. Fig. 9. Curved trichoda, large, the fore-part small, the hinder-part gradually diminishing into a tail; the under part set longitudinally with hairs. _a_, the head; _b_, the tail; _c_, the hairs.

239. TRICHODA PISCIS. T. oblongata, antice crinita, postice in caudam exquisitam attenuata. Plate XXVII. Fig. 13 and 14. Oblong, the fore-part is hairy, the hind-part terminating in a very slender tail. It is smooth, pellucid, much longer than broad, but of nearly an equal breadth throughout, and filled with yellow molecules; the fore-part obtuse, the hind-part exquisitely slender and transparent; the upper side is convex. _a_, the fore-part; _b_, the tail.

240. TRICHODA LARUS. T. elongata, teres, crinita, cuspidi caudali duplici. Long, round trichoda, surrounded with hairs, the tail divided into two points. See Zoologia Danica.

241. TRICHODA LONGICAUDA. T. cylindracea, antice truncata et crinita, cauda elongata, biarticulata et biseta. Plate XXVII. Fig. 10. Cylindrical trichoda, the fore-part truncated and surrounded with hairs, the tail long, furnished with two bristles, and having two joints. _a_, the hairs at the mouth; _d_, the oesophagus; _e_, the articulation of the tail; _f_, the bristles.

242. TRICHODA FIXA. T. sphærica, peripheria crinita, pedicello solitario. Spherical trichoda; this has the circumference set with hairs, and a little solitary pedicle projecting from the body.

243. TRICHODA INQUILINUS. T. vaginata, folliculo cylindrico hyalino, pedicello intra folliculum retortili. Sheathed trichoda, in a cylindrical transparent bag, having a little pedicle bent back within the bag. See Zool. Dan. prodr. addend. p. 281.

244. TRICHODA INGENITA. T. vaginata, folliculo depressa, basi latiore sessilis. Sheathed trichoda, the bag depressed, the base broadest.

The animalculum that is contained in this sheath is funnel-shaped, with one or more hairs, proceeding from each side of the mouth of the funnel. It can extend or contract itself freely in the bag, fixing its tail to the base, without touching the sides. It was found in salt water.

245. TRICHODA INNATA. T. vaginata, folliculo cylindrico, pedicello extra folliculum. Plate XXVII. Fig. 11. Trichoda sheathed in a cylindrical bag, with a pedicle passing through and projecting beyond it. These characters distinguish it sufficiently from the preceding one. _b_, the animalculum in the sheath; _d_, the tail.

246. TRICHODA TRANSFUGA. T. latiuscula, antice crinita, postice setosa, altero latere sinuata, altero mucronata. Broad trichoda, the fore-part hairy, the hinder-part full of bristles; one side sinuated, and the other pointed. See Zool. Dan. prod. addend. p. 281.

247. TRICHODA CILIATA. T. ventricosa, postice crinibus pectinata. Ventricose, the hinder-part covered with hair. See Zool. Dan. Icon. Tab. 73, Fig. 13, 15.

248. TRICHODA BULLA. T. membranacea, lateribus inflexis, antice et postice crinita. Membranaceous trichoda, the sides bent inwards; the fore and hind-part are both furnished with hairs.

249. TRICHODA PELLIONELLA. T. cylindracea, antice crinita, postice setosa. Cylindrical, the fore-part hairy, the hinder-part furnished with bristles.

This trichoda is rather thick in the middle, and pellucid, with a few molecules here and there, the sides obtuse, the fore-part ciliated with very fine hairs, the hind part terminating in a kind of bristles.

250. TRICHODA CYLLIDIUM. T. ovata, apice hiante, basique crinita. Plate XXVII. Fig. 15. Egg-shaped, the apex gaping, the base hairy.

Pellucid, the hinder extremity filled with globules of various sizes, the fore-part narrower, without any appearance of an external organ. It vacillates upon the edge, commonly advancing on its flat side, and continually drawing in water; it then gapes, and opens into a very acute angle, almost to the middle of the body; but this is done so instantaneously, that it is scarcely perceptible. _a_, the mouth; _b_, the hairs or bristles, which it extends when nearly expiring.

251. TRICHODA CURSOR. T. ovata, antice crinita, postice duplici pilorum strictorum et curvorum fasciculo. Oval trichoda, the fore-part hairy, and the hinder-part also furnished with some straight and curved hairs in two fascicles.

The body is flat and filled with molecules; in the fore-part is an oblong empty space, into which we may sometimes see the water sucked in.

252. TRICHODA PULEX. T. ovata, antice incisa, fronte et basi crinita. Plate XXVII. Fig. 12. Egg-shaped, with an incision in the fore-part; the front and base hairy. _a_, the anterior part; _b_, the posterior part; _c_, the incision.

253. TRICHODA LYNCEUS. T. subquadrata, rostro adunco, ore crinito. Plate XXVII. Fig. 16. Nearly square, with a crooked beak, the mouth hairy.

At first sight it does not seem very dissimilar to some of the monoculi. The body is membranaceous, and appears compressed, stretched out into a beak above, the lower part truncated; under the beak is a little bundle of hairs; the lower edge bends in and out, and is surrounded with a few bristles. The intestines are beautifully visible, and a small bent tube goes from the mouth to them in the middle of the body; these, as well as the tube, are in frequent agitation. There is likewise another tube between the fore and hind edge filled with a blue liquor. _a_, the beak; _b_, the mouth; _c_, the base.

254. TRICHODA EROSA. T. orbicularis, antice emarginata, altero latere crinita, postice setosa. Orbicular trichoda, the fore-part notched; one side furnished with hairs, the hinder-part with bristles.

255. TRICHODA ROSTRATA. T. depressa, mutabilis, flavescens, ciliis longis setisque pediformibus. Depressed trichoda, mutable, yellow, with long ciliated hairs, and feet tapering to a point.

The figure of the body is generally triangular; the apex formed into an obtuse beak, which the animalculum sometimes draws in, so that it appears quite round; the feet are four in number, one of them is longer than the rest; both feet and hairs are within the margin. It is found in water where duck-weed has been kept.

256. TRICHODA LAGENA. T. teres, ventricosa, rostro producta, postice setosa. Round ventricose trichoda, with a long neck, and the lower end set with bristles.

257. TRICHODA CHARON. T. cymbiformis fulcata, antice et postice crinita. Plate XXVII. Fig. 17 and 18. Boat-shaped trichoda with furrows, the fore and hind-parts both hairy.

The body is oval; it resembles a boat as well in its motion as shape; the upper part is hollowed, the under part furrowed and convex; the stern round, with several hairs proceeding from it. It was found in salt water. Fig. 17, _a_, the head; _b_, the tail. Fig. 18, _d_, a pellucid bubble that is sometimes to be perceived.

258. TRICHODA CIMEX. T. ovalis, marginibus lucidis, antice et postice crinita. Plate XXVII. Fig. 19. Oval trichoda, with a lucid margin, both the fore and hind-part hairy.

It is about the size of the trichoda lynceus, No. 253, has an oval body, with a convex back, flat belly, and an incision in the margin of the fore-part, the edges of which incision appear to be in motion. Its intestines are pellucid and ill-defined. When it meets with any obstacles in swimming, it makes use of four small bristles, which are fixed to the under side, as feet. _a_, the hairs in the fore-part; _b_, the bristles at the hind-part; _d_, the back; _e_, two small projecting hairs; _f_, the substance to which the animalculum has affixed itself.

259. TRICHODA CICADA. T. ovalis, marginibus obscuris, antice et subtus crinita, postice mutica. Oval trichoda, with an obscure margin, the fore-part covered with hairs on the under side, and the hinder-part beardless.

It does not differ considerably from the preceding, though Müller has pointed out some shades by which they may be discriminated.