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remote. The former are therefore retarded by the tion given above is, therefore, limited to plane latter, while the latter are accelerated by the surfaces. In the case of a heavy fluid it is clear former. There is thus one particle which will be that the centre of pressure of a horizontal area accelerated and retarded to an equal amount, and corresponds with the centre of gravity. When, which will therefore move as if it were a simple | however, the plane is inclined at any angle to the pendulum unconnected with the rest of the body. surface of the fluid, the pressure is not the same at The point in the body occupied by this particle all points, being greater as the depth increases; is called the centre of oscillation.

since in the same liquid the pressure varies with As all the particles of the body are rigidly con. the depth. In general, the centre of pressure will nected, they all vibrate in the same time. Hence be below the centre of gravity. The determination it follows that the time of vibration of the rigid of the centre of pressure requires the use of the body will be the same as that of a simple pendulum, integral calculus, but special cases may be treated called the equivalent or isochronous simple pendu. by ordinary algebra. In the case of a parallelogram, lum, whose length is equal to the distance between one edge of which is in the surface of the fluid, the the centres of suspension and oscillation.

centre of pressure is at a distance of one-third up The determination of the centre of oscillation of a the middle line from the base. In the case of a body requires the aid of the calculus. It may be triangle, having one side in the surface of the fluid, stated, however, that it is always farther from the the centre of pressure is at the middle point of the axis of suspension than the centre of inertia, and is median corresponding to the vertex immersed ; always in the line joining the centres of suspension while in the case of a triangle, with its apex in the

and oscillation. Let A be the centre of sus- surface, and the base horizontal, the centre of
pension, B the centre of inertia, and C the pressure is on the median corresponding to the
centre of oscillation, and let AB be equal to h, vertex and at a distance of three-fourths of the
and k be the radius of gyration of the body | median from the vertex.
about an axis through B parallel to the fixed CENTRE OF BUOYANCY.—The pressures which
axis, then it is easily shown that

act on every point of a surface immersed in a fluid
can be resolved into horizontal and vertical com-
ponents. The former balance one another. The

resultant pressure must therefore be vertical; and, Fig. 3. From this there follows the important pro. as the pressure increases with the depth, it is clear

position that the centres of oscillation and that the upward pressures must be greater than the suspension are convertible, a proposition which was downward. Hence the resultant pressure on an taken advantage of by Kater for the practical immersed body must be a force acting vertically determination of the force of gravity at any | upwards. Now it is easily shown that the magnistation.

tude of this pressure is equal to the weight of the CENTRE OF PERCUSSION.-If a body receive a fuid displaced. The point in the displaced Auid blow which makes it begin to rotate about a fixed at which the resultant vertical pressure may be axis without causing any pressure on the axis, the supposed to act is called the centre of buoyancy, or point in which the direction of the blow intersects centre of displacement. Hence, we see that when a the plane in which the fixed axis and the centre of body floats in a fluid, it is kept at rest by two inertia lie is called the centre of percussion. That forces, the weight of the body acting downwards such a point must exist is easily shown by suspend through its centre of gravity, and the weight of the ing a straight rod by a long string attached to one fluid acting vertically upwards through its centre end, and striking it with a hammer in different of gravity, or centre of buovancy. The relative points. If the rod is struck near the top the foot positions of the centre of gravity and the centre of will move in one direction, and if the blow be buoyancy have an important bearing on tl applied near the foot the top will move in the of ships at sea. If the centre of buoya opposite direction. It is thus evident that there above the centre of gravity, the equilibrium is must be some point which does not move at all at stable; in other words, if the ship is displaced, it the instant of the blow. If a line through this will tend to return to its original position. If, on point be regarded as an axis of rotation, the point the other hand, the centre of buoyancy be below at which the body was struck is the centre of per-| the centre of gravity, the equilibrium will generally cussion, since no pressure is 'roduced on the axis. | be unstable, although a body niay float in stable It is easily proved by means of higher mathematics equilibrium even if the centre of buoyancy be that the centre of percussion with respect to any below the centre of gravity, as is explained in the axis is the same point as the centre of oscillation. article HYDROSTATICS.

From what has been said it is obvious that in CENTRAL FORCES. - Central forces are forces onder that no jar may be felt on the hand a cricket whose action is to cause a moving body to tend ball must be hit in the centre of percussion of the towards a fixed point called the centre of force. bat with respect to an axis through the hand. By Newton's first law of motion we know that

There are, it may be mentioned, many positions every body continues in its state of rest or of which the axis may have in which there will be no uniform motion in a straight line, except in so far centre of percussion. For example, there is no | as it is compelled by forces to change that state.' centre of percussion when the axis is a principal From this we learn that, if the speed of a body axis through the centre of inertia.

changes, or if the line of motion be not straight, CENTRE OF PRESSURE. - When a plane surface whether the speed be unaltered or not, some force is immersed in a fluid at rest, and held in any must be acting. In the latter case the forces acting position, the pressures at different points of the are called central forces. The doctrine of central kuriace are perpendicular to the surface. These forces considers the paths which bodies will describe prezenres may therefore be looked upon as con round centres of force, and the varying velocity &titating a system of parallel forces whose resultant with which they will pass along these paths. It in the whole pressure. The point at which this investigates the law of the force in order that a resultant acts is called the centre of pressure, and given curve may be described, and many other may be defined as the point at which the direction of problems which can only be solved by mathematical the single force which is equivalent to the fluid methods. Gravity affords the simplest illustration pressures on the plane surface meets the surface. of a central force. If a stone be slung from a string, The resultant action of fluids on a curved surface is gravity deflects it from the rectilinear path which not always reducible to a single force. The defini. I it would otherwise pursue, and makes it move in a 68



curve called a parabola. Again, the moon is held Centurion (Lat. centurio, from centum, a in her orbit round the earth by the action of hundred'), a Roman officer commanding a century gravity, which is constantly preventing her from or company of foot-soldiers. There were sixty going off in the line of the tangent to her path at centurions in a Legion (q.v.). any instant.

Ceorl, a word which occurs frequently in the In connection with this subject we have to make

laws before the Norman Conquest under somewhat some remarks on what is called centrifugal force. varying senses, but substantially meaning an ordi. We have seen that force must always be applied to nary freeman not of noble birth. His position make a body move in a curved path. Such a force

gradually sank in social status until it hardly is called a centrifugal force, the old erroneous

differed from that of the serf, save that the ceorl had notion being that bodies have a tendency to fly the right of choosing his own master in accordance outwards from the centre about which they are with the law of Athelstan, which required every revolving. The use of the term will, however, cause landless man to find himself a lord. He still no inconvenience, provided we interpret it merely remained “law-worthy,' and paid his wer-gild of as indicating that, to keep a body moving in a two hundred shillings; but part of his freedom had curve instead of in its natural straight line, à force disappeared, and ultimately his condition developed directed towards the centre of curvature is always into the complete villenage characteristic of feudal. required.

ism. On the other hand, ceorls who possessed land Many familiar illustrations of the action of the

often contrived to force their way into a higher so-called centrifugal force will occur to the reader. I social class, that of the thegns, a kind of nobility A ball fastened to the end of a string, and whirled

of service who may be roughly put as equivalent to round, will, if the motion is sufficiently rapid, at the knights of the period after the Conquest. A last break the string, and fly off in a tangential

ceorl with 5 hides (600 acres) of land was thegnpath. This is due to the fact that the cohesion of

worthy. The name ceor] does not occur in the particles of the string are no longer able to

Domesday—the very degradation of the meaning supply the force necessary to keep the ball moving of the word churl in modern usage is but a part of in its circular path. For a similar reason a fly- | the historical degradation of the social class which wheel or a grindstone bursts when it is made to Lit denoted. rotate too rapidly. It is found that at a curve on a railway it is the outer of the two rails which is

Ceos (sometimes called by the Italianised name most worn. This is due to the fact that the outer

of Zea or Tzia), one of the Cyclades, in the Ægean rail has to supply the force necessary to keep the

Sea, 14 miles off the Attic coast. It is 13 miles trains moving in curved paths. A glass of water

long, 8 broad, and 39 sq. m. in area. The central may be whirled so rapidly that, even when the

and culminating point is Mount Elias, 1863 feet mouth is downwards, the excess of the centrifugal

high. It is fairly fertile, raising fruit, wine, honer, force over the weight of the water is sufficient to

and valonia. The population is 4311, of whom 4295 prevent the water from falling out. The cen.

belong to the capital, Zea or Ceos. In ancient

times Ceos was noted as the birthplace of the poets trifugal force increases with the velocity. As a

| Simonides and Bacchylides, and the physician matter of fact, it can be shown that when a body moves in a circle of radius r, with velocity v, its

Erasistratus; and the Cean laws were famous for

their excellence. centrifugal force is ". By means of this formula

Cephalaspis, a genus of fossil Ganoid fishes, it can be proved that about both of its weight is of which six species have been described, two required merely to keep a body on the earth's

belonging to the Upper Silurian, and four to the surface at the equator. By this amount the weight

Devonian measures. The head was protected by of a body is diminished. Now 289 is equal to 172. a large ganoid plate, sculptured externally with Hence it follows that if the earth were to rotate circular radiating markings. The shield was proseventeen times as fast as it does now, the

duced into a horn at each posterior corner, and bore attraction of gravitation would only just be able at a median and posterior dorsal spine. Agassiz the equator to keep bodies from flying off its surface.

gave the name cephalaspis ('buckler-headed') from If the rotating body be plastic, it will swell out in

this extraordinary covering, which has very much all directions perpendicular to the axis of rotation, the appearance of, and was formerly supposed to and assume the form of an oblate spheroid. For

be, the cephalic shield of an Asaphus or Trilobite. the same reason the earth itself has assumed

The body was covered with rhomboidal enamelled the form of an oblate spheroid, a result which is scales, and furnished with dorsal and pectoral fins : seen on a greater scale in the case of Jupiter and

it terminated in a large unsymmetrical tail. In a Saturn on account of their larger size and more

graphic description of this fossil in his Old Red rapid rotation.

Sandstone, Miller thus sketches the general appearCentre-board. See YACHT, Vol. X. p. 770.

ance of the animal: “Has the reader ever seen a

saddler's cutting-knife-a tool with a crescent. Centrifugal and Centri'petal are terms

shaped blade, and the handle fixed transversely in used in Botany to designate two different kinds of

the centre of its concave side? In general outline, leaf development or inflorescence, the former term

the cephalaspis resembles this tool; the crescent. being applied when the development proceeds from

shaped blade representing the head, the transverse the apex towards the base of the axis or leaf, and

handle the body. The endo-skeleton was mainly the latter when it is from the base upwards towards

cartilaginous, retaining the notochord through life. the apex. See LEAF, INFLORESCENCE.

The flexible body, assisted by the large tail and Centrifugal Force. See CENTRE.

the fins, would give the cephalaspis the power of Centripetal Force. See CENTRE.

moving rapidly through the water. Being a pre. Centum'viri ('a hundred men'), a college of daceous fish, it must have been a formidable enemy justice in ancient Rome, which had jurisdiction in to its associates in the Palæozoic seas, for, besides civil cases. It has been supposed that the body its power of rapid motion, the sharp margin of its was originally made up of three delegates from each shield probably did the work of a vigorously hurled , of the thirty-five tribes. There were 180 members javelin, as in the sword-fish. Pteraspis, Asterolepis in the time of Augustus, and under the emperors it (20 to 30 feet in length), Scaphaspis, Auchenaspis, increased in importance, as it became the only and a number of other genera, are united in the scene left for the display of judicial eloquence and same family as Cephalaspis. See Ray Lankester, of legal knowledge.

| A Monograph of the Fishes of the Bid Red Sand



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stone in Britain, part i. 'Cephalaspidæ' (Lond. | modified to form a funnel through which water is 1868–70); R. H. Traquair, The Ganoids of the squirted. Two or four gills are present in the usual British Carboniferous System (Palæont. Society, Lond. 1877).

Cephalodiscus, one of the most curious and interesting organisms dredged by the Challenger expedition. It was found in the Strait of Magellan, was first supposed to be a compound Ascidian, was monographed (1887) by Professor M‘Intosh as one of the Polyzoa (section Aspidophora), but is regarded by Mr Harmer as closely allied to that marvellous vertebrate-like worm, Balanoglossus (q.v.). The organisms form a spreading seaweed-like brownish colony, measuring in some cases 9 inches by 6, and including a great number of little indi. viduals, protected by a membranous, flexible investment or house. Each individual resembles Balanoglossus (and also in part backboned animals) in many important points, such as (a) the presence of gill-slits; (b) the existence of a notochord as a dorsal outgrowth from the gut, growing forwards into the anterior region or proboscis; and (c) the possession of a dorsal central nervous system, most richly developed in the middle region (or collar), but extending on to the proboscis. As another apparent connecting link between invertebrates and vertebrates, Cephalodiscus is of the greatest

Cuttle-fish (Sepia officinalis), swinming and at rest, zoological interest. See zoology of the voyage of

mantle-cavity. While the ancient forms lived in shells, the Pearly Nautilus alone remains in this state, the shell being in all other cases internal and degenerate. The eyes are peculiarly large, and their ferocious aspect has earned for many common forms the title of devil-fish.' The mouth in the midst of the 'arms' is equipped with parrot-like teeth, and with a rasping ribbon on the tongue. The central nervous system, with its closely associated ganglia, is surrounded by a protective cartilaginous sheath, analogous, though in no way homologous, with a vertebrate brain-box. The sexes are separate. The structure and life of these animals is discussed under the more familiar title CUTTLEFISH; only the general characters, classification, and distribution are here noticed.

Classification.—The Cephalopoda include two distinct orders, one represented by the Pearly Nautilus, the other by all the other living forms, which are again divided into Octopoda and Decapoda, according to the number of the 'arms.' DIBRANCHIATA.

TETRABRANCHIATA. Two gills, kidneys, auricles. Four gills, kidneys, auricles, Eight or ten sucker-bearing Numerous, without suckers.


Shell rudimentary or absent, Shell well developed, external, Cephalodiscus.

never external, in one case chambered.

chambered. An ink-bag.

No ink-bag. H.M.S. Challenger, Part Ixii. ; Report on Cephalo. A completely closed funnel. A split funnel. discus, by Professor W. C. M'Intosh and Mr S. F.

Distribution.-Most species occur in warm and Harmer.

temperate seas, but those found in the colder waters Cephalonia (anc. Cephalenia; Homeric sane), seem much more prolific. The Tetrabranchiata are the largest of the seven Ionian Islands (q.v.), lies the older forms, and begin in the Silurian, whereas opposite the entrance of the Gulf of Lepanto or the Dibranchiata first

the Dibranchiata first appear in Triassic times. Corinth. It is irregular in shape, with a maxi.

The Ammonites (q.v.) are the most familiar remum length of 30 miles, and an area of 302 sq. m. ; presentatives of the former, the Belemnites (q.v.). pop. 80,178. The surface is mountainous, in one of the latter. point attaining 5310 feet; the soil for the most part | See especially CUTTLEFISH, NAUTILUS, BELEMNITES, thin, and water scarce. The inhabitants, however, I AMMONITES ; also CALAMARY, OCTOPUS, SEPIA ; Owen, have planted vineyards wherever the grape will Memoir of the Pearly Nautilus (1832); Férussac grow, and currants and olive-oil are also produced and D'Orbigny, Histoire naturelle des Céphalopodes (2 for export. The capital is Argostoli (q.v.).

vols. Paris, 1835–48); Hoyle, Challenger Report on Cephalo'poda (Gr., 'head-footed'), the highest | Cephalopoda. class of molluscs, and in some respects the highest Cephaloptera, a name formerly used for a invertebrates. They are usually large animals, genus of rays. See RaY. exclusively marine,' with well-developed head Cephissus, one of the two rivers which water region, but (as the quaint name suggests) with the the Athenian plain. It rises on the western slope • foot' or ventral surface grown round the mouth, of Mount Pentelicus and the southern side of and split up into arms,' which (with one excep. Mount Parnes, and flows past Athens on the west tion) bear suckers. Another part of the foot is into the Saronic Gulf near Phalerum.

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Cepola. See BANDFISH.

ally compressed body with large scales, and pos. Ceram' (SERANG), the largest island of the sesses very unfish-like limbs with a central jointed southern Moluccas, lies NE. of Amboyna, to which

axis and lateral pieces. It lives in muddy water Dutch residency it belongs, and is divided into often containing much decaying vegetable matter. Great and Little Ceram by the Isthmus of Taruno.

In this medium it does not find the gill-respiration Area, 6605 sq. m. ; pop. 195,000. The island is sufficient, and comes to the surface to take gulps of one of the least explored in the archipelago, and air into the swimming-bladder, which functions as comparatively little is known of the interior, a lung. It eats leaves and other parts of plants. which is, moreover, but scantily populated, the At nights Ceratodus sometimes leaves the water, great mass of the people, mostly native Alfuros and moves along the river-bank. The expulsion and immigrant Malays, inhabiting the coast of air from its air-bladder or lung is supposed to villages. Much of the island is very fertile. A account for a grunting noise then often heard. mountain-chain runs through the country, reach In the dry season it buries itself in the mud. ing in Nusa Keli some 11,000 feet. The chief exports are sago, iron, timber, earthenware, birds of Paradise, dried fish, edible nests, &c.

Ceram'ics (Gr. keramos, potter's clay'), a term used to designate the department of plastic art which comprises all objects made of clay, such as vases, cups, bassi-rilievi, cornices, and the like. See POTTERY.

Cerastes, or HORNED VIPER, a genus of serpents of the family Viperidæ, distinguished by a

Limb of Ceratodus. broad depressed heart-shaped head, the scales of which are similar to those of the back, and partic. The flesh is much esteemed, and compared with ularly remarkable for the development of one of salmon. This interesting animal is discussed, in the scales of each eyelid into a spine or horn, often its more technical relations, along with its neighof considerable length. The tail is very distinct bour genera-Lepidosiren and Protopterus—under

the title MUD-FISHES.

Ceratonia. See CAROB.

Cerberus, in Greek Mythology, the many. headed dog-according to Hesiod, the offspring of Typhaon and Echidna—who guarded the portal of tlie infernal regions. Later writers describe him as only three-headed, with the tail and mane composed of serpents, though the poets sometimes encumber him with a hundred heads. Orpbeus charmed him by the magic of his lyre, and Hercules overcame him by strength and dragged him to the upper

world. Horned Viper (Cerastes vulgaris).

Cercarria, the technical name applied to an

embryonic form of many flukes. In all the twofrom the body. This genus is exclusively African,

suckered flat parasitic worms (the Distomeæ and very venomous. There is probably only one

division of Trematodes) the development is indirect species, Cerastes ægyptiacus or cornutus, the Horned

or circuitous. The eggs develop into embryos, Viper of the north of Africa, called Cerastes by

which, instead of growing into adults, produce the ancients, the name being derived from the Greek keras, a horn.' It was correctly described

asexually one or more sets of intermediate forms.

The final form, produced more or less directly from by the traveller Bruce, but his description was for

| the embryo, is called a cercaria, and grows up into some time regarded with incredulity.

the adult fluke. It differs from the adult in having Cerate (Lat. cera, ‘wax'), a compound of wax only rudiments of reproductive organs, in possessing with other oily and medicinal substances in such eye-spots, and in being (except in one genus) proportions as to have the consistence of an oint

| equipped with a very movable tail. It is (1) born ment (see OINTMENTS). Simple cerate is made by | within some host, such as a water-snail ; (2) leaves melting together 6 parts of olive oil, 3 of white this and swims freely in the water; (3) becomes wax, and I of spermaceti.

sluggish, and enters a second host, or fixes itself on Ceratites, a genus of Ammonites (q.v.) some foreign body. In this state it loses its tail peculiar to, and characteristic of, the Trias.

and encapsules itself, and does not experience any Cerat'odus, the Queensland mud-fish, one of further change till (4) it or its host is eaten by a the remarkable sub-class of double breathers or vertebrate, within which the cercaria becomes an Dipnoi. The name was originally used for the

adult and sexual fluke. From the latter the emfossil possessors of certain tooth-plates found in the

bryos which eventually enter the first-mentioned host arise. Sometimes the life-history is simpler, but in all cases the cercaria is the form produced (generally indirectly) by the original embryo, and developing into the adult. See FLUKE.

Cercis. See JUDAS' TREE.

Cercopithe'cus (Gr., tail-ape'), a genus of

monkeys. See MONKEY. Ceratodus.

Cere (in natural history). See BILL

Cerea’lia, or CEREAL GRASSES, SO named Triassic and Jurassic strata, and to this genus the from Ceres (q.v.), are the plants which produce Queensland survivor, which has similar dental grain or corn; in strictness, all the species of arrangements, was referred when discovered in 1870. grasses (Gramineæ ) cultivated for the sake of their Barra munda is the local name. The fish may seed as an article of food. They are also called occasionally attain a length of six feet, has a later. Corn-plants or Bread-plants; but in this wide

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popular sense the term cereal ceases to have any eases, such as acute and chronic Hydrocephalus botanical linits, and includes plants of wholly (q.v.), it is greatly increased, and then it becomes distinct orders, notably Buckwheat (natural a cause of atrophy of the brain. Its value as a order, Polygonacese), and Quinoa (Chenopodi. water-cushion in diminishing the violence of shock acer), &c. ; even the Lotus of the Nile, the Vic. from external injury has been already referred to toria regia, and other species of water-lilies might at BRAIN. Cerebro-spinal means pertaining to the thus be added to the list.

brain and spinal cord together, to the cerebroThe cereals proper do not belong to any particular spinal system. For Cerebro-spinal Meningitis, see tribe of the great order of grasses, but the employ. | MENINGITIS. ment of particular species as bread-plants seems to | · Cerebrum. See BRAIN. have been determined chiefly by the superior size of

Ceremonies, MASTER OF THE, an officer at the seed, or by the facility of procuring it in suffi

court, instituted by James I. for the reception of cient quantity, and of freeing it from its unedible

ambassadors and dignitaries. The same name came envelopes. The most extensively cultivated grains

to be used for the supreme authority on etiquette are Wheat (Triticum), Barley (Hordeum), Rye

at public assemblies at Bath and elsewhere; Beau (Secale), Oats (Avena), Rice (Oryza), Maize or Indian Corn (Zea), different kinds of Millet

Nash (q.v.) being the most memorable. (Setaria, Panicum, Paspalum, Pennisetum, and

Cereopsis (Gr., 'wax-face'), a genus of birds Penicillaria), and Durra or Guinea Corn (Sorghum

of the family Anatidæ, to which the New Holland or Andropogon). These have all been cultivated

goose (C. novæ hollandic) belongs. This bird has from time immemorial, and there is great uncer.

been known since the southern shores of Australia tainty as to the number of species to which the many

were first visited by navigators. There, and on the existing varieties belong; their original forms and

adjacent islands, they were found in great abund. native countries often cannot confidently be deter

ance; and so little were they acquainted with the mined. Barley, oats, and rye are the grains of the

danger to be apprehended from man, that the coldest regions, the cultivation of the former two

earlier navigators easily supplied themselves with extending even within the arctic circle. Wheat is

fresh provisions by knocking them down with

sticks." The flight is slow and heavy, and the next to these, and in the warmer regions of the temperate zone its cultivation is associated with

bird is naturally becoming less abundant. The cere that of maize and rice, which are extensively culti.

(see BILL) is remarkably large, whence the name. vated within the tropics. The millets belong to | Ceres, the Roman name of the great Greek warm climates, and durra is tropical or sub-tropical. | goddess Dēmētēr, the protectress of agriculture and Rice is the food of a greater number of the human the fruits of the earth. Her worship was borrowed race than any other kind of grain. See Corn, by the Romans from Sicily. Her first temple in BARLEY, MAIZE, MILLET, RICE, WHEAT, and | Rome was vowed by the dictator A. Postumius other separate articles.

Albinus (496 B.C.), to avert a famine with which Cerebration, UNCONSCIOUS. There can be

the city was threatened. A great festival, with

games, the Cerealia, was instituted in her honour, no doubt that molecular changes in the cerebrum

and her worship acquired great importance in the accompany all our conscious mental processes. The

city. The decrees of the senate were deposited doctrine of unconscious cerebration as stated by

in her temple for the inspection of the tribunes Carpenter, Laycock, and others, holds that similar

of the people. See DEMETER. changes may go on in the cerebrum without any consciousness on our part, until the fully elaborated

Ceres, one of the Planetoids (9.v.), and the mental result is presented. It is an every day

first of them that was discovered. It was first seen experience that after one has been in vain trying to by Piazzi at Palermo, January 1, 1801, and is recall some name or incident, it will suddenly flash

sometimes visible to the naked eye, looking like a into the mind when one is thinking of some entirely star between the seventh and eighth magnitudes. ditierent subject. According to Carpenter the cere. Cereus, a large genus of Cactaceæ (q.v.), con. brum put in action by our consciousness has gone taining many of the most imposing forms of the on working automatically but unconsciously, until order, both as respects vegetation and towering. the processes accoinpanying the mental operation | C. giganteus reaches a height of 60 feet, often unof remembering the name or incident have been branched, its tall pillars giving an extraordinary completed. This is the physiological statement character to the landscape of New Mexico, while corresponding to the psychological doctrine that the the allied C. peruvianus (36 feet) takes its place in mind may undergo modifications without being | Peru. Others have thin snake-like branches (C. conscious of the process until the new combination flagelliformis), while the short obconical C. senilis is presented to consciousness. See CONSCIOUSNESS, 'is covered with long silky hairs. Many have BRAIN, PSYCHOLOGY, PERSONALITY.

splendid flowers, and of these C. speciosissimus with Cerebro-spinal Fluid is a clear, almost

scarlet or purplish flowers is often cultivated, while colourless, slightly alkaline fluid, closely resem.

C. grandiflorus is the well-known night-flowering lling lymph in its composition, but containing less

cactus. The fruits are often much esteemed. For albumen. It is contained partly within the ventric.

illustration, see CACTUS. ular system of the brain, and in part in the loose Cerignola, a town of Italy, 22 miles SE. of connective tissue (subarachnoid meshwork), which Foggia by rail, with manufactures of linen, and a lies between the Arachnoid and Pia Mater (g.v.), trade in almonds and cotton. The Spaniards' deci. being continued from this latter situation along sive victory over the French here in 1503 established the lymphatic sheaths, which closely invest all Spain's supremacy in Naples. Pop. 22,659. the blood vessels in the substance of the brain Ceri'go, the southernmost of the seven Ionian and spinal cord. The spaces which contain it com Islands (q.v.), now officially known again by its old municate with the lymphatics of the head and of Greek name of Cythera, is separated from the coast the nerves, and with the venous sinuses in the of Morea by a narrow strait. Area, 107 sq. m.; dura mater. Its main function, besides that of pop. (1879) 13,259. It is mostly barren and mounfrmoving waste products, is to equalise the pressure | tainous in some parts; but corn, wine, and olives within the skull. As the blood pressure increases and fruits are raised. Capsali is the capital. In that of the cereliro-spinal fluid diminishes, and rice ancient times the island was sacred to Venus, as rers. As the brain atrophies it is replaced by a the land that received the goddess when she arose proportionate increase in the fluid. In some dis. | from the sea.

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