internal structure, and much more imperfect vital properties than those of the preceding orders. They possess no external nor internal skeleton, and exhibit no trace of nervous or muscular fibres. They are marine animals of a soft gelatinous transparent texture, and move freely to and fro, supported in the water by the contractility of their fleshy substance, aided in some of the species by vesicles filled with air. There are sometimes several entrances to the stomach, but there is no anus distinct from the mouth. They have no distinct organs of circulation or respiration, but vessels or cœca are observed proceeding from the stomach and ramifying through the substance of the body. Many of these animals present beautiful contrasts of colours in their transparent texture, and elegant external plant-like forms. They appear to abound chiefly in the colder latitudes of the ocean. They often change the colour of great tracts of the sea from their abundance. They produce the sparkling luminosity often observed by night in the agitated waves of the ocean. They serve as the food of whales, whose masticating organs appear to be adapted for no other kind of food. They present a kind of ovo-gemmiparous generation, and the ova of the Medusa Aurita have been observed to possess a power of spontaneous motion when first separated from the parent, as in Zoophytes. They have no apparent organs for impregnation, nor any distinction of sex. The mouth is in the centre of the lower part of the body, and is generally surrounded with numerous ramified appendices. Many of those animals possess a stinging property when touched in the living state with the naked hand, hence the term applied to them by Cuvier, Acalephæ (from xxxon a nettle). The genera of this order are, 10. Rhizophysa. 1. Beroe. 12. Medusa. 13. Equorea. 14. Foveola. * 18. Aurelia. 2. Callianira, 11. Sephanomia. 19. Cassiopea. 20. Lymnorea. 21. Favonia. 22. Geryonia. 23. Berenice. 24. Eudora. 3. Ceste. 4. Diphia. 5. Porpita. 6. Vilella. 15. Phorcynia. 7. Noctiluca. 16. Cyanea. part supported by an axis or skeleton composed of cartilaginous, horny, calcareous, or silicious substance. The soft parts have a simple gelatinous texture and soft consistence, destined for the function of digestion, and exhibiting no distinct organs Zoophytes are either for secretion or generation. gemmiparous, some generating by the discharge of internal gemmules, and others by forming gemmules on their surface, which separate when they have attained maturity. The internal gemmules have an ovoidal or round form, and soft gelatinous consistence like small ova, and appear, from the observations of Dr. Grant on the zoophytes of the Frith of Forth, to be almost always ciliated on the surface, and capable of moving to and fro in the water, by the rapid vibration of their cilia for some time after their separation from the body of the parent. The small apertures on the surface of Zoophytes for lodging the polypi are called cells, the capsules for containing the gemmules are which surround the named vesicles, the arms mouths of the polypi are the tentacula, and the very minute vibratory processes like short hairs which fringe the tentacula are the cilia. The cells of zoophytes are permanent parts, and their forms afford the most useful characters for distinguishing The vesicles for containthe species and genera. ing the gemmules in the flexible horny zoophytes appear only at particular seasons of the year, and fall off when the gemmules have escaped. In some zoophytes, as the Flustræ and Cellariæ, the reproductive gemmules are formed in the cells of the polypi, and the polypi and gemmules succeed each other repeatedly during the life of the animal. There are sometimes more than one row of tentacula round the mouths of the polypi, as in Tubulariæ, Caryophylliæ, &c.; most frequently there is but one row, consisting of from 6 to nearly 30 tentacula; 8 is a frequent number in the most highly organized species. In some of the simplest zoophytes the tentacula are entirely wanting. The cilia are generally disposed around the margins of the tentacula; in most zoophytes they are vibratory, causing, by their motions, currents in the surrounding water to flow towards the mouths of the 8. Physalia. 17. Rhizostoma. 25. Carybdea. polypi. As the fixed condition of zoophytes pre9. Physsophora. CLASS III.-ZOOPHYTA. The animals of this class present a more complicated and diversified external form, but a more simple internal organization than those of the two preceding classes. They are aquatic animals of a plant-like form, generally compound, and fixed by their base. They possess no distinct organs of sense, nor any trace of a nervous, muscular, or circulating system. Their digestive organs consist of numerous small superficial sacs termed polypi, having a single aperture, surrounded with tentacula or cilea, for attracting and seizing prey. They have generally a spreading base, a stem and branches, and shoot up from the bottom of the sea, or hang from the roofs of submarine caves, or are attached to plants, rocks, shells, or other submerged substances. Their body is for the most VOL. XVIII.-PART II. vents them from moving to and fro like other animals in search of food, the cilia are adapted to bring it to their mouths from a distance. The cilia are very numerous on each tentaculum, and move with incalculable rapidity. Sometimes more than two thousand cilia are observed on a single polypus, and we have calculated more than three hundred millions of vibratory cilia on a single specimen of the Flustra foliacea. When there are no tentacula, the cilia are disposed around the entrance of the digestive sac, as in Vorticellæ. Like other gemmiparous animals, zoophytes have no distinction of sex. In many of the genera the gemmules make their appearance in clustres at the base of the polypi, and pass out through their bodies. Zoophytes appear to feed principally on Infusoria, they required only the existence of that class to prepare the sea for their creation, and their re4 W mains form the oldest fossil animals met with in the strata of the earth. They are used in medicine, in domestic economy, and in the arts. Corals are formed into various ornamental articles. The sponge is a valuable article of commerce, and extensively used in the arts. Madrepores are used as building materials in countries where limestone is scarce, and many calcareous zoophytes are used as manure. Rocks, bays, and fertile islands owe their existence to these animals in tropical seas. They organise matter for the digestive organs of higher animals, particularly for the mollusca and the minutest crustacea. They precipitate, in form of a carbonate, an immense quantity of lime continually pouring by rivers, in a soluble form, into the bed of the ocean, and thus prepare the abyss for the maintenance of vertebrate animals. The interesting researches of Imperati, Marsigli, Donati, Peysonnel, Cavolini, Olivi, and Schweigger, on the species of the Mediterranean, those of Trembley on the Hydræ, those of Reaumur, Jussieu, and Lamouroux on the species of the coast of France, those of Peron and Lesueur on the Zoophytes of the southern hemisphere, and, above all, those of our countryman Ellis, on the species of the British coasts, have greatly extended our acquaintance with the structure and economy of this class of animals. The useful labours of Bruguiere and Esper, the accurate and detailed descriptions of Pallas, the elaborate and interesting details of Lamouroux, and the acute discriminations and beautiful views of Lamarck, have eminently contributed to determine the true relations of these animals to each other, and advance the natural history of zoophy tes. The following orders are founded on the divisions pointed out by Lamarck, and for the most part retain the names and the order of succession that distinguished naturalist has assigned them. ORDER 1.-Calamoida, Gr. Calamides, Latr. The zoophytes of this order have been erroneously conceived to possess the power of swimming to and fro in the sea by the sudden elevation and depression of their lateral pinnæ, or by the successive strokes of the arms of the polypi, and they were thence termed polypi natantes by Lamarck. They are all marine animals, of a lengthened form, and possessing an internal calcareous axis. Their polypi have eight tentacula disposed in a single row around the mouth, and their cilia are long and not vibratory. They are not attached by their base, but either lie loose at the bottom of the sea, or are carried to and fro by the waves. The united bodies of the polypi form the principal fleshy part of the zoophyte, and the reproductive gemmules which make their appearance first at the bases of the polypi, pass out through the mouths of these organs, as we have observed in the Pennatula phosphorea and Virgularia mirabilis. These gemmules in several of the species are ciliated on the surface, and possessed of spontaneous motion. They are named Calamoida from their resemblance, in form, to a quill or feather. To this order belong the genera. ORDER 2.-Tubifera, Lamarck. This term is applied by Lamarck to a small group of zoophytes, the polypi of which are enveloped by distinct tubes which open on the surface of the body. They are fixed zoophytes, with a fleshy contractile body, and without a calcareous axis. The polypi in this group have, like those of the preceding order, eight tentacula around the mouth, and the cilia of these tentacula are not vibratory organs, but appear to be only supplementary to the tentacula. The ova or gemmules of the Lobularia are ciliated on the surface, and pass out through the bodies of the polypi as in the preceding order. The genera of this order are, 1. Lobularia. 3. Xenia. 2. Ammothea. 4. Anthelia. ORDER 3.-Carnosa. The body is composed of a soft gelatinous substance, supported by a fibrous axis of a cartilaginous, horny, calcareous or silicious nature. Some, as the Alcyonium, have distinct polypi with numerous tentacula furnished with vibratory cilia; others, as the Halina and Leucalea have no polypi, of internal canals passing through every part of the and appear to have the cilia disposed on the sides body. In this order alone we meet with a silicious axis, and a soft gelatinous body almost destitute of inert genera of this order, are ciliated on the surirritability. The ova or gemmules in the most face, and swim by the vibration of these cilia, as in the other orders. The genera of this order are, 1. Alcyonium. 4. Cliona. 7. Halina. 2. Geodia. 5. Spongia. 8. Flabellaria. 5. Tethya. 6. Leucalia. 9. Penicillus. ORDER 4.-Corticifera, Lamarck. In the zoophytes of this order there is an internal axis of a calcareous or horny nature, sometimes regularly jointed. The axis is covered with a soft irritable fleshy substance, in which the polypi have their cells, there are consequently no cells observed on the internal axis. From the experiments so often and carefully repeated by Cavolini on the living Gorgonia verrucosa, in the bay of Naples, it is obvious that the fleshy crust of these zoophytes is the most essential and important part-the part which secretes the successive layers of the axis, and forms the polypi. The polypi have eight tentacula, and the reproductive gemmules pass out through the bodies of the polypi. The gemmules of the Gorgonia move by means of their cilia. The red coral of commerce belongs to this group of zoophytes. The Corallina, generally placed in fessor Schweigger of Konigsberg to be only a calthis order, appears, from the experiments of Procified plant. The genera of this order are, 1. Gorgonia. 3. Isis. 5. Corralium. ORDER 5.-Lamellifera, Lamarck. This extensive order comprehends most of the large and elegant tropical species of the calcareous zoophytes, whose vast operations in the seas of the southern hemisphere are so well calculated to excite our admiration, and to interest the attention of the navigator. They have a calcareous axis, often of great density, and marked on the surface with radiated, stellular, or undulated impressions formed by thin elevated lamellæ. In the recent state the whole body is covered with a soft gelatinous flesh, in which the polypi are lodged. The gemmules are formed in clusters at the base of each polypus, and pass out through these organs. The genera of this order are, 13. Fungia. ORDER 7.-Reteformia, Lamarck. spe horny substance, forms tubular cells or sheaths The axis of the zoophytes, belonging to this group, is composed of delicate calcareous expansions generally cellular or reticulated, and never forms compact masses as in some of the preceding orders. The surface is composed of minute shallow cells, arranged for the most part in regular series, for the lodgment of the polypi, and for the formation of the gemmules. The polypi have generally very numerous tentacula furnished with vibratory cilia. The polypi and gemmules appear, from observations made on several species of the Frith of Forth, to succeed each other alternately in the same cells, and in those which have been examined the gemmules are irritable, and have cilia on their surface, by which they move freely to and fro after their separation. The calcareous zoophytes most common in our northern latitudes belong to this order. The genera are, 2. Ocellaria. 1. Dactylopora. 5. Adeona. 9. Tubulipora. ORDER 8.-Vaginiformia, Lamarck. 11. Sertularia. 12. Campanularia. 13. Cornularia. 8. Serialaria. ORDER 9.-Lacustria. This order comprehends a few fresh water genera grouped together more by their abode than their organization. Three of the genera are fixed zoophytes, and the other two move freely to and fro. They are found encrusting stones and other objects on the margin of fresh water lakes. They form irregular masses perforated on the surface by the cells of the polypi, or by canals which traverse their whole interior. The polypi have an incomplete circle of tentacula around the mouth. In the Spongilla there are pores and internal canals without polypi. The genera of this order are, 3. Spongilla. 4. Cristatella. 1. Plumatella. 5. Difflugia. ORDER 10.-Denudata, Lamarck. Lamarck has comprehended under this name the four genera, Zoantha, Pedicellaria, Coryna, and Hydra. The first of these belongs to the Radiata. The second appears to be merely organs of the Echini on which it is always found. The other two genera are distinguished by being naked, soft, fleshy zoophytes, without any distinct axis. The tentacula in these genera are not furnished with vibratory cilia. They present an external gemmiparous mode of generation. The Hydræ are all fresh water animals, and the Corynæ are found only in the sea. Genera. 1. Coryna. 2. Hydra. ORDER 11.-Ciliata, Lamarck. This order comprehends the minutest and simplest animals of the whole class. From their smallness, and their body being generally free, they were classed among the Infusoria by former naturalists. Their body is naked, soft, transparent, and without any distinct internal axis or skeleton. There are no tentacula around the mouths of the polypi, but the margin of the oral disk is surrounded with 4 W 2 vibratory cilia. Some of these animals are beautifully ramified, and all the ramifications are composed of the same gelatinous contractile substance as the polypi. They are called Ciliata by Lamarck, from the cilia supplying in them the place of the tentacula of the other orders. The genera of this order are 1. Tubicolaria. 4. Furcularia. 7. Vaginicola. 2. Norticella. 5. Brachionus. 8. Trichocerca. 3. Urceolaria. 6. Folliculina. 9. Rattulus. CLASS IV.-INFUSORIA, Lam. (Agastrica Latr). in the waters of lakes and rivers. They are the food of zoophytes. We have found them in incalculable myriads in the water of harbours, and along our coasts, and at many miles distance from land among the Western Islands, and they probably abound not only in the waters of tropical seas, but in every drop of the ocean. They possess great tenacity of life. They suffer exposure to very high and very low temperatures without perishing. They may be dried to hardness, and again resuscitated by the application of moisture. According to the experiments of Baker, Needham, and others, they may be revived by moisture, after remaining many years in a dried and apparently lifeless state. They form by far the most numerous class of beings with which we are acquainted, although, from the difficulty of examining their structure and economy, they have least engaged the attention of naturalists. These animals were discovered by Lewenhoek, who has described and figured many of the species. Muller has greatly extended our acquaintance with this class by his numerous, accurate, and full descriptions, and elegant coloured delineations of infusoria. The labours of Bruguiere in the Encyclop. Method. form also a valuable contribution. Baker, Needham, Ledermuller, Roesel, Buffon, Schrank, Baron Gleichen, Spallanzani, Lamarck, Bory de St. Vincent, Prevost, and Dumas, have added greatly to our knowledge of the Infusoria by their interesting observations on the economy of the species, or by their general views of their classification. They are called Agastrica by Latreille, from their having no internal stomach; Protozoa by Meckel, from their being in all probability the first formed of animals; Microscopica by Bory St. Vincent, from their minuteness. This class has been divided by most writers into three distinct groups, which may be considered as orders, though still founded on unimportant characters, viz. Appendiculata, Membranacea, and Incrassata. The class of Infusory animalcules, as now defined by Lamarck, is limited to those microscopic, transparent, gelatinous, aquatic animals, of a simple structure and form, which are destitute of an internal digestive sac or stomach, and are nourish ed by superficial absorption. They are found only in fluids. They present no trace of an osseous, muscular, nervous, or vascular system, nor any distinct internal organs for respiration, secretion, or generation. They generate either by a simple division of their body, or exhibit a gemmiparous mode of generation. The minutest animalcules discoverable by the aid of the microscope appear only as transparent moving points, or extremely minute gelatinous globules, without any perceptible external or internal parts. Some present a coloured and somewhat opaque point in their centre, others are distinctly observed to move by the vi-bration of very minute cilia variously disposed on their surface. In many animalcules we perceive a distinct internal cavity, which contains, not food, but the young, in form of minute globular gemmules, as in the Volvox and Enchelis. The body of the parent sometimes bursts to allow the escape of the young, and these species thus perish, like most insects, after a first generation. Many Infusoria have distinct external appendices, generally in form of a single or of a bifurcated tail. Some present circles of vibratory cilia on the anterior extremity of the body which, when in motion, appear like rotating wheels. The simplest animalThis order comprehends the most highly orcules, as the monads, give origin to new individuals, by their bodies gradually dividing either ganized species belonging to this class, some of transversely or longitudinally, a mode of generation which make a near approach to the simplest of the which is termed fissiparous. This fissiparous mode ciliated zoophytes. They present distinct projectof generation is compatible only with the simplest ing parts, variously situated on the surface of the kind of internal organization, and accords with di- body, sometimes extending from the anterior part rect observation in proving their almost homoge-like tentacula or like feet, and sometimes from the neous internal structure. Blumenbach, and many other naturalists, have been led by numerous experiments to believe that some kinds of animalcules may originate from mere combinations of the elements of vegetable or animal matter in a fluid state, without the aid of a previously existing parent. They have no distinction of sex, nor organs of generation. The spermatic animalcules which abound in the seminal fluid of all classes of the higher animals, form a connecting link between this class and the simplest Entozoa. Animalcules abound in decayed infusions of vegetable or animal matter, in decayed vinegar, in the secreted fluids of animals in the living state, in all stagnant waters, and ORDER 1.-Appendiculata. posterior extremity like a simple or a bifurcated 3. Kerona. ORDER 2. Membranacea. The animalcules of this order have a simpler form and structure than the preceding. They have generally a depressed or flattened body, with an ovoidal or circular form. They have not those projecting parts like members seen in the former order. The body is sometimes long, slender and flattened like a membrane, as in some of the Kolpodæ, in others it is nearly circular, as in the Cyclidium, in others irregularly ovoidal, as in the Paramecium, and in others angular, as in the Gonium. In the Bursaria, the absorbing surface of the animalcules is increased by the body being concave or hollow like a purse, which probably also affords a safer position for the development of the reproductive gemmules. This order is composed of the genera, ORDER 3. Incrassata. This order comprehends the smallest and simplest animalcules hitherto discovered by the aid of the microscope. They have neither the external appendices of the first order, nor the flattened membranous form of the second, but have generally a spherical, oblong, or cylindrical body. They are termed Incrassata from the thickness of the body compared with its other dimensions. In some the body has a regular spherical form, as in some Monades and Volvoces; some of the Enchilides have the body pear-shaped or fusiform, and in many of the Vibriones it is of a lengthened cylindrical serpentine form. The genera of this order are ZUI ZUINGLE, ULRIC, a celebrated Swiss reformer, was born on January 1, 1484, at Wildhausen, and fell in the battle at Cappel between the Catholic and Protestant cantons in October 1531, in the 47th year of his age. See our article ECCLESIASTICAL HISTORY. ZURICH, CAanton of. See SWITZERLAND. ZURICH, a city of Switzerland, and capital of a canton of the same name, is beautifully situated on the lake of Zurich, where the river Limmat discharges itself. This river, which divides the city into two parts, is crossed by three bridges. It may also be crossed at the flour-mills, which are built in the middle of this river. The principal public buildings are the cathedral, the Maison des Orphelins, the Meiser, the Maison de Ville, the Helmshouse which contains the library, the Cassino, and the churches of Notre Dame and St. Pierre. The cathedral is a large Gothic building, but destitute of those beauties which belong to that style of architecture. It consists of a body and two square towers 262 feet it height, placed at the southern extremity of the church. The towers are square, and built of stone for about two-thirds of their height. The rest, which is polygonal and terminating in a pointed dome, is built of wood and is covered with copper on the outside. The seats in the cathedral turn up, and each has arms like an arm-chair. It contains two churches. The cathe ZUR front and five windows in a line on the side, and is three stories high. The Meiser is a very neat public building on the south-east side of the river, and at the end of the High Bridge. It has six Ionic columns in front, and is three stories high. There are eleven windows in a line in front, and seven in a line in the side. The centre windows both at the front and side have a large balcony of stone. Above each window is a sculptured ornament. Above the centre of the building is a semicircular pediment with a triangular pediment on each side of it. The cabinet Physiognomique is contained in this building. The Maison de Ville is an elegant building, begun in 1794. It is built upon the river (which runs below it), at the north-east extremity of the low wooden bridge. It is a mixture of Greek and Gothic, and is three stories high. The first storey has Tuscan pilasters, the second Ionic, and the third Corinthian. There are nine windows in a line in front and three in depth, each window having above it a semicircular and a tringular pediment alternately. Above the windows of the first storey all around there are placed within the pediments statues of eminent men. The list commences with Junius Brutus, Cocles, Scævola, all the rest being chiefly Swiss. The name of the person is engraven on the stone, and an appropriate Latin motto is carved beneath each. The principal door is of black marble, with a gilt lion above each column. In the lobby are two pictures containing representations of all the fish found in the lake, to the number of 30. The Helmhouse is built a little farther up the river on the same side, and at the north-east extremity of the Haut Pont. It is a good building, with arcades and shops below, and contains the public library |