Part 25

[Illustration: FIG. vii.--Diagram of a mode of progression of a Ciliate like _Paramecium_; m, mouth and pharynx; the straight line A, B, represents the axis of progression described by the posterior end, and the spiral line the curve described by the anterior end; the clear circles are the contractile vacuoles on the dorsal side.]

The position of the free-swimming Infusoria, like that of Rotifers and other small swimming animals, is with the front end of the body inclined outward to the axis of advance, constantly changing its azimuth while preserving its angle constant or nearly so; if advance were ignored the body would thus rotate so as to trace out a cone, with the hinder end at the apex, and the front describing the base. On any irritation, (1) the motion is arrested, (2) the animal reverses its cilia and swims backwards, (3) it swerves outwards away from the axis so as to make a larger angle with it, and (4) then swims forwards along a new axis of progression, to which it is inclined at the same angle as to the previous axis (figs. vi., vii.). In this way it alters its axis of progression when it finds itself under conditions of stimulation. Thus a _Paramecium_ coming into a region relatively too cold, too hot, or too poor in CO2 or in nutriment, alters its direction of swimming; in this way individuals come to assemble in crowds where food is abundant, or even where there is a slight excess of CO2. This reaction may lead to fatal results; if a solution of corrosive sublimate (Mercuric chloride) diffuses towards the hinder end of the animal faster than it progresses, the stimulus affecting the hinder end first, the axis of progression is altered so as to bring the animal after a few changes into a region where the solution is strong enough to kill it. This "motile reaction," first noted by H. S. Jennings, is the explanation of the general reactions of minute swimming animals to most stimuli of whatever character, including light; the practical working out is, as he terms it, a method of "trial and error." The action, however, of a current of electricity is distinctly and immediately directive; but such a stimulus is not to be found in nature. The motile reaction in the Hypotrichaceae which crawl or dart in a straight line is somewhat different, the swerve being a simple turn to the right hand--i.e. away from the mouth.

Parasitism in the Infusoria is by no means so important as among Flagellates. _Ichthyophthirius_ alone causes epidemics among Fishes, and _Balantidium coli_ has been observed in intestinal disease in Man. The Isotricheae, among Aspirotrichaceae and the Ophryoscolecidae among Heterotrichaceae are found in abundance in the stomachs of Ruminants, and are believed to play a part in the digestion of cellulose, and thus to be rather commensals than parasites. A large number of attached species are epizoic commensals, some very indifferent in choice of their host, others particular not only in the species they infest, but also in the special organs to which they adhere. This is notably the case with the shelled Peritrichaceae. _Lichnophora_ and _Trichodina_ (fig. iii. 8, 9) among Peritrichaceae are capable of locomotion by their permanent posterior wreath or of attaching themselves by the sucker which surrounds it; _Kerona polyporum_ glides habitually over the body of Hydra, as does _Trichodina pediculus_.

Several Suctoria are endoparasitic in Ciliata, and their occurrence led to the view that they represented stages in the life-history of these. Again, we find in the endosarc of certain Ciliates green nucleated cells, which have a cellulose envelope and multiply by fission inside or outside the animal. They are symbiotic Algae, or possibly the resting state of a Chlamydomonadine Flagellate (_Carteria_?), and have received the name _Zoochlorella_. They are of constant occurrence in _Paramecium bursaria_, frequent in _Stentor polymorphus_ and _S. igneus_, and _Ophrydium versatile_, and a few other species, which become infected by swallowing them.

_Classification._

Order I.--Section A.--Gymnostomaceae. Mouth habitually closed; swallowing an active process; cilia (or membranelles) uniform, usually distributed evenly over the body; form variable, sometimes of circular transverse section.

Section B.--Trichostomata. Mouth permanently open against the endosarc, provided with 1 or 2 undulating membranes often prolonged into an inturned pharynx; ingestion by action of oral ciliary apparatus.

Order 2.--Subsection (a).--Aspirotrichaceae. Cilia nearly uniform, not associated with cirrhi or membranelles, nor forming a peristomial wreath. Form usually flattened, mouth unilateral. (N.B.--Orders 1, 2 are sometimes united into the single order Holotrichaceae.)

Subsection (b).--Spirotricha. Wreath of distinct membranelles--or of cilia fused at the base--enclosing a peristomial area and leading into the mouth.

§§ i.--Wreath of separate membranelles.

Order 3.--Heterotrichaceae; body covered with fine uniform cilia, usually circular in transverse section.

Order 4.--Oligotrichaceae; body covering partial or wholly absent; transverse section usually circular.

Order 5.--Hypotrichaceae; body flattened; body cilia represented chiefly by stiff cirrhi in ventral rows, and fine motionless dorsal sensory hairs.

Order 6.--§§ ii.--Peritrichaceae. Peristomial ciliary wreath, spiral, of cilia united at the base; posterior wreath circular of long membranelles; body circular in section, cylindrical, taper, or bell-shaped.

_Illustrative Genera (selected)._

1. Gymnostomaceae. (a) Ciliation general or not confined to one surface. _Coleps_ Ehr., with pellicle locally hardened into mailed plates; _Trachelocerca_ Ehr.; _Prorodon_ Ehr. (fig. i. 6, 7); _Trachelius_ Ehr., with branching endosarc (fig. i. 8); _Lacrymaria_ Ehr. (fig. i. 5), body produced into a long neck with terminal mouth surrounded by offensive trichocysts; _Dileptus_ Duj., of similar form, but anterior process, blind, preoral; _Ichthyophthirius_ Fouquet (fig. i. 9-12), cilia represented by two girdles of membranellae; _Didinium_ St. (fig. i. 13), cilia in tufts, surface with numerous tentacles each with a strong terminal trichocyst; _Actinobolus_ Stein, body with one adoral tentacle; Ileonema Stokes. (b) Cilia confined to dorsal surface. _Chilodon_ Ehr.; _Loxodes_ Ehr., body flattened, ciliated on one side only, endosarc as in _Trachelius_; _Dysteria_ Huxley, with the dorsal surface hardened and hinged along the median line into a bivalve shell, ciliated only on ventral surface, with a protrusible foot-like process, and a complex pharyngeal armature. (c) Cilia restricted to a single equatorial girdle, strong (probably membranelles); _Mesodinium_, mouth 4-lobed.

2. Aspirotrichaceae. _Paramecium_ Hill (fig. ii. 1-3); _Ophryoglena_ Ehr.; _Colpoda_ O. F. Müller; _Colpidium_ St.; _Lembus_ Cohn, with posterior strong cilium for springing; _Leucophrys_ St.; _Urocentrum_ Nitsch, bare, with polar and equatorial zones and a posterior tuft of long cilia; _Opalinopsis_ Foetlinger (fig. i. 1, 2); _Anoplophyra_ St. (fig. i. 3, 4). (The last two parasitic mouthless genera are placed here doubtfully.)

3. Heterotrichaceae. (a) Wreath spiral; _Stentor_ Oken. (fig. iii. 2), oval when free, trumpet-shaped when attached by pseudopods at apex, and then often secreting a gelatinous tube; _Blepharisma_ Perty, sometimes parasitic in Heliozoa; _Spirostomum_ Ehr., cylindrical, up to 1´´ in length; (b) Wreath straight, often oblique; _Nyctotherus_ Leidy, parasitic anus always visible; _Balantidium_ Cl. and L., parasitic (_B. coli_ in man); _Bursaria_, O.F.M., hollowed into an oval pouch, with the wreath inside.

4. Oligotrichaeceae. _Tintinnus_ Schranck (fig. iii. 3); _Trichodinopsis_ Cl. and L.; _Codonella_ Haeck. (fig. iii. 5); _Strombidium_ Cl. and L. (fig. iii. 4), including _Torquatella_ Lank. (fig. iii. 6, 7), according to Bütschli; _Halteria_ Duj., with an equatorial girdle of stiff bristle-like cilia; _Caenomorpha_ Perty (fig. iii. 23, 24); _Ophryoscolex_ St., with straight digestive cavity, and visible anus, parasitic in Ruminants.

5. Hypotrichaceae. _Stylonychia_ Ehr.; _Oxytricha_ Ehr.; _Euplotes_ Ehr. (fig. i. 14, 15); _Kerona_ Ehr. (epizoic on _Hydra_).

6. Peritrichaceae. 1. Peristomial wreath projecting when expanded above a circular contractile collar-like rim.

(a) Fam. Urceolaridae: posterior wreath permanently present around sucker-like base. _Trichodina_ Ehr. (fig. iii. 8, 9), epizoic on Hydra; _Lichnophora_ Cl. and L.; _Cyclochaeta_ Hatchett Jackson; _Gerda_ Cl. and L.; _Scyphidia_ Duj.

(b) Fam. Vorticellidae = Bell Animalcules: posterior wreath temporarily present, shed after fixation.

Subfam. 1. Vorticellinae animals naked. (i.) Solitary; _Vorticella_ Linn. (fig. iii. 11-17), stalk hollow with spiral muscle; _Pyxidium_ S. Kent, stalk non-contractile. (ii.) Forming colonies by budding on a branched stalk: _Carchesium_ Ehr., hollow branches and muscles discontinuous; _Zoothamnium_. Ehr., branched hollow stem and muscle continuous through colony; _Epistylis_ Ehr., stalk rigid--(the animal body in these three genera has the same characters as _Vorticella_)--_Campanella_ Goldf., stalked like _Epistylis_, wreath of many turns (nematocysts sometimes present) (fig. iii. 19); _Opercularia_, stalk of _Epistylis_, disk supporting wreath obconical, collar very high (fig. iii. 20).

Subfam. 2. Vaginicolinae; body enclosed in a firm theca: _Vaginicola_ Lam., shell simple, sessile; _Thuricola_ St. Wright, shell sessile, with a valve opening inwards (fig. iii. 25-26); _Cothurnia_ Ehr., shell stalked, simple; _Pyxicola_ S. Kent, shell stalked, closed by an infraperistomial opercular thickening on the body (fig. iii. 21-22).

Subfam. 3. Shells gelatinous; those of the colony aggregated into a floating spheroidal mass several inches in diameter _Ophrydium_ Bory, _O. versatile_ contains _Zoochlorella_, which secretes oxygen, and the gas-bubbles float the colonies like green lumps of jelly.

2. Peristomial wreath, not protrusible, surrounded by a very high usually spiral collar.

Fam. Spirochonina. _Spirochona_ St. (fig. iii. 10); _Kentrochona_ Rompel; both genera epizoic on gills, &c., of small Crustacea.

SUCTORIA.--These are distinguished from Ciliata by their possession of hollow tentacles (one only in _Rhyncheta_, fig. viii. 1, and _Urnula_) through which they ingest food, and by not possessing cilia, except in the young stage. Fission approximately equal is very rare. Usually it is unequal, or if nearly equal one of the halves remains attached, and the other, as an embryo or gemmule, develops cilia and swims off to attach itself elsewhere; _Sphaerophrya_ (fig. viii. 2-6) alone, often occurring as an endoparasite in Ciliata, may be free, tentaculate and unattached.

The ectosarc is usually provided with a firm pellicle which shows a peculiar radiate "milling" in optical section, so fine that its true nature is difficult to make out; it may be due to radial rods, regularly imbedded, or may be the expression of radial vacuoles. The tentacles vary in many respects, but are always retractile. They are tubes covered by an extension of the pellicle; this is invaginated into the body round the base of the tentacle as a sheath, and then evaginated to form the outer layer of the tentacle itself, over which it is frequently raised into a spiral ridge, which may be traced down into the part sunk and ensheathed within the body: in _Choanophrya_, where the tentacles are largest, the pellicle is further continued into the interior of the tentacle. The tentacles are always pierced by a central canal opening at the apex, which may be (1) enlarged into a terminal capitate sucker, (2) slightly flared, (3) truncate and closed in the resting state to become widely opened into a funnel, or (4) pointed. The tentacles are always capable of being waved from side to side, or turned in a definite direction for the reception or prehension of food; in _Rhyncheta_, the movements of the long single tentacle recall those of an elephant's trunk, only they are more extensive and more varied. In the majority of cases the food consists of Ciliata; and the contents of the prey may be seen passing down the canal of the sucker beyond where it becomes free from the general surface. In _Choanophrya_ the food appears to consist of the débris of the prey of the carnivorous host (_Cyclops_), which is sucked into the wide funnel-shaped mouths of the tentacles--by what mechanism is unknown. The endosarc is full of food-granules and reserve-granules (oil, colouring matter and proteid).

[Illustration: FIG. viii.--Suctoria (in all a, meganucleus; b, contractile vacuole).

1, _Rhyncheta cyclopum_, Zenker; only a single tentacle and that suctorial; epizoic on Cyclops.

2, _Sphaerophrya urostylae_, Maupas; normal adult; parasitic in Ciliate _Urostyla_.

3, The same dividing by transverse fission, the anterior moiety with temporarily developed cilia.

4, 5, 6, _Sphaerophrya stentorea_, Maupas. Parasitic in _Stentor_, and at one time mistaken for its young.

7, _Trichophrya epistylidis_, Cl. and L.

8, _Hemiophrya gemmipara_, Hertwig. Example with six buds, into each of which a branch of the meganucleus a is extended.

9, The same species, showing the two kinds of tentacles (the suctorial and the pointed), and two contractile vacuoles b.

10, Ciliated embryo of _Podophrya steinii_, Cl. and L.

11, _Acineta grandis_, Saville Kent; showing pedunculated cup, and animal with two bunches of entirely suctorial tentacles.

12, _Sphaerophrya magna_, Maupas. It has seized with its tentacles, and is in the act of sucking out the juices of six examples of the Ciliate _Colpoda parvifrons_.

13, _Podophrya elongata_, Cl. and L.

14, _Hemiophrya benedenii_, Fraip.; the suctorial tentacles retracted.

15, _Dendrocometes paradoxus_, Stein. Parasitic on Gammarus pulex; captured prey.

16, A single tentacle of _Podophrya_. R. Hertwig.

17-20, _Dendrosoma radians_, Ehr.:--17, free-swimming ciliated embryo. 18, Earliest fixed condition of the embryo. 19, Later stage, a single tentaculiferous process now developed. 20, Adult colony; c, enclosed ciliated embryos; d, branching stolon; e, more minute reproductive (?) bodies.

21, _Ophryodendron pedicellatum_, Hincks.]

The meganucleus and the micronucleus are both usually single, but in _Dendrosoma_ (fig. viii. 20), of which the body is branched, and the meganucleus with it, there are numerous micronuclei. In most cases the micronucleus has not been recorded, though from the similarity of conjugation, and its presence in most cases of fission and budding that have been accurately described, we may infer that it is always present. In unequal fission the meganucleus sends a process into the bud, while the micronucleus divides as in Ciliata. The bud may be nearly equal to the remains of the original animal, or much smaller, and in that case a depression surrounds it which may deepen so as to form a brood-cavity, either communicating by a mere "birth-pore" with the outside or entirely closed. In some cases the budding is multiple (fig. viii. 8), and a large number of buds are formed and liberated at the same time. In all cases the bud escapes without tentacles, and possesses a characteristic supply of cilia, whose arrangement is constant for the species.

In some cases an adult may withdraw its tentacles, moult its pellicle and develop an equipment of cilia and swim away: this is the case with _Dendrocometes_, parasitic on _Gammarus_, when its host moults.

The numerous species of Suctoria, often so abundant on various species of _Cyclops_, are not found on the other freshwater Copepoda, _Diaptomus_ and _Canthocamptus_, belonging indeed to other families. Again, these Suctoria affect different positions, those found on the antennae not being present on the mouth parts; the ventral part of the thorax has another set; and the inside of the pleural fold another. _Rhyncheta_ occupies the front of the "couplers" or median downgrowths uniting the coxopodites of the swimming legs, and _Choanophrya_ settles in the immediate neighbourhood of the mouth, preferably on the epistoma, labrum and metastomatic region, but also on the adoral appendages and in rare cases extends, when the settlement is extensive, to the bases of the two pairs of antennae; while distinct species of _Podophrya_ settle on the antennae, the front of the thorax and the inside of the pleural folds. _Dendrocometes_ is common on the gills of the freshwater shrimp (Amphipod) _Gammarus_ and _Stylocometes_ on the gills and gill-covers of the Isopod Asellus, the water-slater. The independence of the Acinetaria was threatened by the erroneous view of Stein that they were phases in the life-history of Vorticellidae. Small parasitic forms (_Sphaerophrya_) were also regarded erroneously as the "acinetiform young" of Ciliata. They now must be regarded as an extreme modification of the Protozoon series, in which the differentiation of organs in a unicellular animal reaches its highest point.

_Principal Genera._

1. Unstalked simple forms. _Urnula_ Cl. and L., permanently ciliate; _Rhyncheta_ Zenker (fig. viii. 1), on the limb couplers of _Cyclops_; _Sphaerophrya_ Cl. and L. (fig. viii. 2-6, 12), endoparasitic in Ciliata and formerly taken for embryos thereof, never attached; _Trichophrya_ Cl. and L. (fig. viii. 7), of similar habits, but temporarily attached, sessile.

2. Stalked simple forms; _Podophrya_ Ehr. (fig. viii. 10, 13, 16), tentacles all knobbed or flared; _Ephelota_ Strethill Wright, tentacles all pointed; _Hemiophrya_ S. Kent (fig. viii. 8, 9, 14), tentacles of both kinds; _Choanophrya_ Hartog, tentacles thick, truncate, very retractile, when expanded opening into funnels for aspiration of floating prey, never for attachment--epizoic on antero-ventral parts of _Cyclops_.

3. Cupped forms; _Solenophrya_ Cl. and L., cup sessile; _Acineta_ Ehr., cup stalked; _Acinetopsis_ Bütschli, like _Acineta_, but the cup flattened, closed distally with only slit-like apertures ("pylomes") for the bundles of tentacles; _Podocyathus_, like _Acineta_, but with pointed as well as knobbed tentacles.

4. Tentacles in bundles at the tips of one or more processes or branches of the body. _Ophryodendron_ Cl. and L., tentaculiferous process single (fig. viii. 21); _Dendrocometes_ Stein (fig. viii. 15), body rounded, processes repeatedly branched, epizoic on gills of _Gammarus pulex_; _Dendrosoma_ Ehr. (fig. viii. 17-20), body freely branched from a basal attached stolon, meganucleus branching with the body.

BIBLIOGRAPHY.--(a) Infusoria in the widest sense: C. E. Ehrenberg. _Die Infusionstierchen als vollkommene Organismen_ (1838); F. Dujardin, _Zoophytes infusoires_ (1841). (b) Infusoria, including Mastigophora: M. Perty, _Zur Kenntniss Kleinster Lebensformen_ (1852); E. Claparède and J. Lachmann, _Études sur les infusoires_ _et les Rhizopodes_ (1858-1861); F. von Stein, _Der Organismus der Infusionstiere_ (1859-1883); W. Saville Kent, _A Manual of the Infusoria_, including a description of all known Flagellate, Ciliate and Tentaculiferous Protozoa (1880-1882). (c) Infusoria, as limited by Bütschli. O. Bütschli, _Bronn's Tierreich_, vol. i. _Protozoa_, pt. 3 _Infusoria_ (1887-1889), the most complete work existing, but without specific diagnoses; S. J. Hickson, "The Infusoria" in Lankester's _Treatise on Zoology_, vol. i. fasc. 2 (1903), a general account, well illustrated, with a diagnosis of all genera. See also Delage and Hérouard, _Traité de Zoologie concrète_, vol. i. "La Cellule et les Protozoaires" (1896), with an illustrated conspectus of the genera; E. Maupas, "Recherches expérimentales sur la multiplication des Infusoires ciliés," _Arch. zool. exp._ vi. (1888); and "Le Rajeunissement karyogomique chez les Ciliés," _ib._ vii. (1889); R. Sand, _Étude monographique sur le groupe des Infusoires tentaculifères_ (Suctoria), (1899), with diagnoses of species; A. Lang, _Lehrb. der vergleich, Anatomie der wirbellosen Tiere_, vol. i. "Protozoa" (1901) (a view of comparative anatomy, physiology and bionomics); Marcus Hartog, "Protozoa," in _Cambridge Natural History_, i. (1906); H. S. Jennings, _Contributions to the Study of the Behaviour of Lower Organisms_ (1904); G. N. Calkins, "Studies on the Life History of Protozoa" (Life cycle of Paramecium), I. _Arch. Entw._ xv. (1902), II. _Arch. Prot._ i. (1902), III. _Biol. Bull._ iii. (1902), IV. _J. Exp. Zool._ i. (1904). Numerous papers dealing especially with advances in structural knowledge have appeared in the _Archiv für Protistenkunde_, founded by F. Schaudinn in 1902. (M. Ha.)

INGEBORG [INGEBURGE, INGELBURGE, INGELBORG, ISEMBURGE, Dan. INGIBJÖRG] (c. 1176-1237 or 1238), queen of France, was the daughter of Valdemar I., king of Denmark. She married in 1193 Philip II. Augustus, king of France, but on the day after his marriage the king took a sudden aversion to her, and wished to obtain a separation. During almost twenty years he strained every effort to obtain from the church the declaration of nullity of his marriage. The council of Compiègne acceded to his wish on the 5th of November 1193, but the popes Celestine III. and Innocent III. successively took up the defence of the unfortunate queen. Philip, having married Agnes of Meran in June 1196, was excommunicated, and as he remained obdurate, the kingdom was placed under an interdict. Agnes was finally sent away, but Ingeborg, shut up in the château of Étampes, had to undergo all sorts of privations and vexations. The king attempted to induce her to solicit a divorce herself, or to enter a convent. At last, however (1213), hoping perhaps to justify by his wife's claims his pretensions to England, Philip was reconciled with Ingeborg, whose life from henceforth was devoted to religion. She survived him more than fourteen years, passing the greater part of the time in the priory of St Jean at Corbeil, which she had founded.

See Robert Davidson, _Philip II. August von Frankreich und Ingeborg_ (Stuttgart, 1888); and E. Michael, "Zur Geschichte der Königin Ingelborg" in the _Zeitschrift für Katholische Theologie_ (1890).

INGELHEIM (Ober-Ingelheim and Nieder-Ingelheim), the name of two contiguous market-towns of Germany, in the grand-duchy of Hesse-Darmstadt, on the Selz, near its confluence with the Rhine, 9 m. W.N.W. of Mainz on the railway to Coblenz. Ober-Ingelheim, formerly an imperial town, is still surrounded by walls. It has an Evangelical church with painted windows representing scenes in the life of Charlemagne, a Roman Catholic church and a synagogue. Its chief industry is the manufacture of red wine. Pop. (1900) 3402. Nieder-Ingelheim has an Evangelical and a Roman Catholic church, and, in addition to wine, manufactories of paper, chemicals, cement and malt. Pop. 3435.

Nieder-Ingelheim is, according to one tradition, the birthplace of Charlemagne, and it possesses the ruins of an old palace built by that emperor between 768 and 774. The building contained one hundred marble pillars, and was also adorned with sculptures and mosaics sent from Ravenna by Pope Adrian I. It was extended by Frederick Barbarossa, and was burned down in 1270, being restored by the emperor Charles IV. in 1354. Having passed into the possession of the elector palatine of the Rhine, the building suffered much damage during a war in 1462, the Thirty Years' War, and the French invasion in 1689. Only few remains of it are now standing; but of the pillars, several are in Paris, one is in the museum at Wiesbaden and another on the Schillerplatz in Mainz. Inside its boundaries there is the restored Remigius Kirche, apparently dating from the time of Frederick I.

See Hilz, _Der Reichspalast zu Ingelheim_ (Ober-Ingelheim, 1868); and Clemen, "Der Karolingische Kaiserpalast zu Ingelheim," in _Westdeutsche Zeitschrift_, Band ix. (Trier, 1890).