F. Cuvier observes, that the Pacas are, among the Omnivorous Rodents, what the Capybaras are among the Herbivorous section. The first possess molars with roots distinct from their crowns, to the number of 4 on each side of either jaw. Those of the upper jaw are nearly of a size; but, in the lower, they diminish gradually from the last to the first. All the molars, before they have been subjected to the process of mastication, present, on the upper surface of the crown, 4 tubercles, which more or less completely divide the tooth broadwise, and are separated by three transverse furrows, more or less large or deep. When the crown of the tooth is exposed to mastication, the top of the tubercles begins to wear away, and the enamel, instead of forming a sort of hood or cap, presents a series of riband-like foldings, the outlines of which are conformable to the tubercles and furrows. In proportion to the continuance of the abrasion, the tubercles are successively effaced; and, finally, nothing is to be seen but the enamel, which hoops the tooth externally, and that which penetrates the interior and is there complicated, the plaits going very deep, so that the ribands of enamel, whose edges are exposed on the triturating surface, change their appearance with the age of the animal, and terminate by disappearing in a great measure.

The Pacas approach the Capybaras and the Agoutis most nearly, and are closely allied to the latter by their general form and the similarity of their organisation. The dental and generative systems in both are very nearly alike; neither have clavicles, nor indeed has the Capybara; and though the Agouti has only three toes on the hind feet, the two additional hind toes of the Paca are hardly more than rudiments. The great differences consist in the zygomatic development, the folding back of the skin under the zygomatic arch-and the consequent bluff appearance of the head-the cheek-pouches, and the fur.

F. Cuvier records two species, C. subniger and C. fulvus; but Baron Cuvier, in the last edition of the 'Règne Animal,' treats them as varieties of the same species.

C. Paca (Reugger), the Paca. It is the Mus Paca, Linnæus; Cavia Paca, Schreber; C. subniger, F. Cuvier; C. niger, F. Cuvier; Osteossera platycephala, Harlan; Le Pag, D'Azara.

Its general appearance reminds the observer of the Pachydermatous animals, for it is thick-set and stubby. The legs are thick, the neck short, the head heavy, the body rounded, the gait clumsy, but the motions of the animal are prompt and sudden. All the feet have five toes, which anteriorly have the ordinary proportions, but posteriorly the analogues of the little toe and great toe are extremely short in proportion to the rest, and almost rudimentary, like the upper or lateral toes in the hog. The claws are conical, thick, and strong, and proper for digging. The tail is reduced to a naked immoveable tubercle, a few lines in length. The principal male organ is directed backwards, and there is no external appearance of the testicles. The external ear is moderate in size, rounded, and simple. There is nothing particular about the eye, the pupil of which is round. The nostrils, which are large and almost united, open transversely at the muzzle. The tongue is very soft, short, and thick. The upper lip is divided, the interior of the mouth is furnished with cheek-pouches, and, externally, the large area formed by the development of the zygomatic arch is lined on its inner surface with a continuation of the skin of the cheeks, which is reflected from the face, so as to form a hollow pouch, of which there is no other example among mammiferous animals, and the use of which it is difficult to divine, if the great development of the zygomatic arch be not destined to preserve the true cheek-pouches (abajoues) from external shocks. Strong whiskers spring from the sides of the muzzle, and from behind the eye. The fur is composed of silky hairs, very short, very thin, and very stiff, of a blackish-brown on all the upper parts of the body, excepting four rows of parallel spots, which begin at the shoulders and terminate at the buttocks: the spots of each row are so approximated, that when viewed in a particular direction they seem to form an uninterrupted line, and the row nearest the belly is almost confounded with the colour of that part, which is white, as well as the under parts of the lower jaws, the internal surface of the limbs, and the claws. Length of the body, from the occiput to the insertion of the tail, 16 inches: length of the head, from the occiput to the end of the muzzle, 5 inches. Height, to the shoulders 12 inches-to the top of the buttocks (train de derrière) 14 inches, French. (F. Cuvier.) This animal is better known as the Paca of zoologists generally, and, after the Capybara and Coypu, is one of the largest of the South American Rodents. It is the Spotted Cavy of Pennant and Bewick, the Pag of the Brazilians, Paig of the inhabitants of Paraguay, Ourana of some of the tribes of Guyana and Pakiri of others, the Pak of the colonists of Cayenne, and the Water-Hare of those of Surinam. In all these countries it is common, with the exception of Paraguay, where, according to D'Azara, it is very rare. They formerly existed in the islands of the West Indies.

In a state of nature the habitation of the Paca is in low humid forests, and in the neighbourhood of water. The animal digs a burrow like the rabbit, but much less deep; indeed it is so near the surface, that the foot of the pedestrian often breaks through, and, sinking into the tunnel, drives out the tenant. There are generally three issues to a burrow, and the aperture of these the animal covers with dry leaves and branches. To take it alive, the hunter stops two of these

apertures, and digs into the third; but when the penetralia are reached, the hapless besieged makes a most determined resistance, fighting the enemy with ferocity, and trying to bite. When undisturbed, it often sits up and washes its head and whiskers with its two fore paws, which it licks and moistens with its saliva at each ablution, like a cat; and with these fore paws, as well as with the hind ones, it often scratches itself and dresses its fur. Though heavy and corpulent, it can run with a good deal of activity, and often takes lively jumps. It swims and dives with great adroitness, and its cry resembles the grunting of a young pig. Its food consists of fruits and tender plants, which it seeks in the night, hardly ever quitting its burrow in the day, the strong light of which, as is the case with other nocturnal animals, is oppressive to its eye. The planter often rues the visits made by these midnight foragers to his sugar-canes. The female is said to bring forth at the rainy season, and to produce but a single young one, which stays a long time with the mother. The Pacas are very cleanly creatures, never dropping their excrements near their dwellings, but going to a considerable distance for that purpose.

In captivity, according to F. Cuvier, no animal can exhibit less intelligence. When offended, it throws itself violently at the object which has displeased it, and then makes a grumbling, which breaks out into a kind of barking; and when it is not eating it is sleeping. But it requires a soft and well-made bed; and, to obtain this, it collects with its mouth hay, herbage, straw, anything indeed that suits its purpose, of which it makes a little heap, and then lies down in the centre of it. This bed it never defiles, but goes to the extremity of its cage the farthest removed from it, and constantly resorts to the same spot for the same purpose. If, says F. Cuvier, it is but little favoured on the side of intelligence, it appears on the other hand to be recompensed by a large share of instinct, to judge, at least, by appearances. Mr. Bennett, from his observation of one which lived for some months in the Garden of the Zoological Society in the Regent's Park, says that it is quiet and contented in captivity. Buffon, who kept one for some time in his house, found it familiar and mild.

The flesh is stated to be excellent and of good flavour; but as it is very fat and rich, it soon cloys: it is prepared for cookery by being scalded like a sucking pig. Piso gives the following character of its merits for the table :-"Carne est tenera, pingui lardo non indigens, si assetur, sed inter epulas magnatum, sicut lepores et caprem in Europa, habetur." Its skin is of no value to the furrier; but its thickness might make it available in the useful arts. F. Cuvier thinks that it would be possible to introduce this animal into our European rural establishments, and that it would form a very good acquisition in the department of domestic economy.

C. laticeps (Lund) is a fossil species founded upon a cranium from the caverns of Brazil. In this species the surface of the frontal bone and zygomatic arch are smooth. It also differs from the last species in the infra-orbital opening being larger, the upper part of the bony ring which incloses it narrower, and the zygoma is thrown more boldly forwards. Dr. Lund distinguishes a second species from the same caverns, which he calls C. major. It is much larger than the last. Mr. Waterhouse says, "From the caverns above alluded to the British Museum contains numerous remains referrible to the genus Calogenys. The most characteristic specimen among these is a considerable portion of a skull, in which I can find no points which would lead me to suppose it belonged to a species distinct from the common Paca." COELOPTY CHIUM, a genus of Spongiada, proposed by Goldfuss, for some fossils of the Chalk.

aromatic ruminated substance to a nutmeg. It is a secretion formed in the interior of the seed, and enveloping the embryo plant, for whose support it is destined when it first begins to germinate; it constitutes the principal part of the seed, the embryo itself being a minute body lying in a cavity at one end of the albumen. Unskilful observers are often unable to find the embryo; but it may readily be seen by the following simple means:-Take a new sample of small fine unroasted Mocha coffee, and throw it into boiling water; the embryo will, after a little while, be expelled with force from the albumen in a majority of cases.

Coffea Arabica is an ever-green shrub, with oval shining wavy sharp-pointed leaves, white fragrant five-cleft clustered corollas with projecting anthers, and oblong pulpy berries, which are at first of a bright red, but afterwards become purple. It is stated by Niebuhr to have been brought from Abyssinia to Yemen by the Arabs from a country similar to their own plains and mountains. By that people it has for ages been cultivated in the hilly range of Jabal, in a healthy temperate climate, watered by frequent rains, and abounding in wells and water-tanks. Here the plants are grown in grounds that are continually irrigated, and in soil from one to one and a half foot deep. Among the plantations are interspersed various kinds of trees, whose shade has a beneficial effect upon the coffee-bushes. When in flower, they diffuse a most delicious fragrance, in the midst of which the natives fix their habitations. The fruit begins to ripen in February; and when the seeds are prepared, they are conveyed to the city of Beit el Fakih, whence part goes to Mocha, and another portion to Hodeida and Loheia, whence it finds its way to Djedda and Suez for the Turkish and European markets.

Coffee Plant (Coffea Arabica).

The seed of Coffea Arabica consists of much horny albumen, and a peculiar principle or alkaloid, termed Caffeine, which contains more nitrogen than any other known vegetable substance. The seed is used in a raw state in medicine, and, when roasted, both as a medicine and still more extensively as an article of diet. The coffee-plant begins to produce fruit when two or two and a half years old; but the quality of the seeds from young stems is not so good as that from stems four or five years old. The size and colour of the bean (as the inner part of the seed is called) vary considerably, those from the West Indies being larger than those from the East. Much more depends upon the manner of roasting and making the coffee, than upon the quality of the bean. The superiority of French coffee, in the preparation of which little or no Mocha coffee is used, proves this position. Beans of a good quality are hard and heavy, sink quickly in water, are of a odour of coffee, which though faint is peculiar, and are free from any damp smell. Beans recently collected, or only two or three months from the tree, are not so good as those about a year old; when older than this they become deteriorated. From the analysis of Seguin and Schröder, coffee consists of coffee-bitter (impure caffeine), solid fat, resin, a little aromatic principle, gum, albumen (this albumen, according to Seguin, unites with the yellow coffee-bitter, and forms a green), and lignin. The taste of raw coffee is somewhat sweetish; but the application of heat in the process of roasting produces important changes. The bean increases to nearly twice the original size, while it loses about one third of its weight: a powerful and agreeable odour is evolved, and a large quantity of empyreumatic oil, which appears in small drops on the surface, is formed along with a bitter principle, probably by an alteration in the caffeine, and of the saccharine matter. The roasting should take place in a close revolving iron cylinder, over a clear but moderate fire, and should not be carried too far: when the beans have acquired a light chestnut colour, the roasting should be discontinued. The beans are then to be cooled quickly by being tossed up into the air, and the grinding, or rather rough pounding, should be performed in a covered mortar or mill. The drink should be prepared from it as soon as possible, by infusion, which is preferable, unless some apparatus be employed by which a kind of decoction is made in a close vessel. About half an ounce of coffee powder should be used for every eight ounces (half a pint) of water. În Britain the roasting is generally carried too far; and the subsequent parts of the process, instead of being performed immediately, are often postponed for days or even weeks, by which the aroma is dissipated: when made the liquid is generally deficient in strength and clearness. The employment of white of egg or fish-skin for clarification is decidedly objectionable: clearness is thus purchased, but at the expense of the strength.

The addition of milk (which should always be hot) and of sugar heightens the nourishing qualities of this beverage, and in the morning renders it a more substantial article for breakfast. When taken after dinner to promote digestion it should be without milk, and, where the palate can be reconciled to it, without sugar.

There is much uncertainty as to the first introduction of coffee into the western parts of Europe. The Venetians, who traded with the Levant, were probably the first to use it. We find it mentioned in the year 1615 by Peter de la Valle, and thirty years after this some gentlemen returning from Constantinople to Marseille brought with them a supply of this luxury, together with the vessels required for its preparation.

Coffee was first introduced into England in the year 1652, fourteen years earlier than the introduction of tea. The first coffee-house was opened in George Yard, Lombard Street, by a Greek named Pasque, who was brought from Turkey by a merchant of the name of Edwards.

The adulterations of ground coffee are very considerable; the most important of these is chicory, a dark brown powder made from the roasted roots of the Chicorium Intybus. It is perfectly harmless, and by some is thought to be an agreeable addition to the coffee: it is not however of so much value, and should not therefore be added to the coffee by the dealer, but sold separately, so that those who desire to add it may purchase it themselves. Various other seeds are used either as imitations or adulterations of coffee, such as Rye-Chick Peas (Cicer arietinum), Broom Seeds (Spartum scoparium), the Yellow Water-Iris (Iris pseudacorus), and the Dandelion root (Leontodon taraxacum). It has been suggested to use the leaves of the coffee-plant in infusion the same as those of the tea-plant, and it is said they form a very agreeable beverage; but the berries are too valuable in themselves to

Richness of soil in the West Indies has been thought to be the cause of the inferior quality of coffee grown in that part of the world, and to the supposed dryness of Yemen has been ascribed the excellence of Mocha coffee. But it has been shown that the Arabs counteract the effect of any dryness in the air by abundant irrigation; and that moreover it is not in the Tehama or dry parts of the country that it is cultivated, but on hill-sides, where the temperature is much lower, and where it rains daily for four months in the year.

would be were there any demand for them as an article of diet. For medical uses, trade, and cultivation, see COFFEE, in ARTS AND Sc. Div.

COIX, a genus of Plants belonging to the natural order of Grasses. One of the species, C. Lachryma, has hard stony fruits, which are known by the name of Job's Tears. These fruits are supposed by some writers to be strengthening and diuretic. COLAPTES. [PICIDE.] COLARIS. [CORACIAS.] COLCHICACEAE. [MELANTHACEÆ.]

COLCHICUM, a genus of Plants belonging to the natural order Melanthacea. It has a coloured funnel-shaped perianth, with a very long subterranean slender tube, and a somewhat campanulate 6-parted limb; 6 stamens inserted into the throat of the tube; a 3-celled ovary; numerous ovules in 2 or 4 rows; 3 long filiform styles; stigmas somewhat clavate; capsule 3-celled, 3-partible, opening inwardly; seeds numerous, roundish, with a shrivelled skin.

C. autumnale, Meadow Saffron, is a plant with a solid bulb-like rootstock, found wild in various parts of Europe, as well as in Great Britain, and forming a gay carpet in the autumn in the fields, where its lively purple crocus-like flowers spring up. Its under-ground stems, or bulbs, as they are called, and its seeds, abound in an acrid stimulating deleterious principle, which has been carefully examined by modern chemists, and the plant forms an important article in the Materia Medica, large quantities of both rootstocks and seeds being annually consumed in the manufacture of Eau Médicinale, and other medicinal preparations. The rootstock is irregularly egg-shaped, and covered with a dry brittle brown skin; at its base it bears a bud, which feeds upon the parent stock, exhausting and finally replacing it every year. Its flowers are large, pale purple, and spring up in the autumn without leaves, forcing themselves readily through the soil, and expanding just their orifice, together with the anthers and stigmas, above the surface of the soil, while the tubular part with the ovary and filaments, remains enveloped in membranous sheathing spathes below the soil. Each stock produces six or eight of these flowers. The stamens are six, the ovaries three, each with a long thread-shaped style, and not adhering in any degree to the tube of the flower. These are succeeded by three little follicles, which slightly adhere to one another by their inner edge, and in the spring are elevated above the soil by their lengthened footstalk. At this time, too, the foliage makes its appearance in the form of an erect tuft of broad, oblong, shining, sheathing leaves. Each follicle contains several oblong seeds. It is found in the moist rich pastures of England, and in various other countries of Europe.

Colchicum is so very like an autumn crocus that an inexperienced observer might readily mistake the one for the other. They are however to be distinguished by the crocus having only three stamens, one style, and an inferior ovary, while the Colchicum has six stamens, three styles, and a superior ovary distinctions of no little importance when the poisonous qualities of Colchicum, in which the crocus does not at all participate, are considered.

For medicinal purposes the rootstocks of Colchicum should be collected at Midsummer, and they should be used immediately; for at that time the peculiar principles which they contain are in the greatest state of concentration. If they are employed at a time when the plant is in a state of growth, especially when it is coming into flower, those principles are partly lost and decomposed by the growth of the plant, and there is no certainty as to the quantity of Colchicine that a given weight of the rootstocks will yield.

Other species of Colchicum are cultivated for the sake of their flowers, but they are of no medicinal importance, and are very badly distinguished from each other by botanists.

Three different parts of C. autumnale yield an active principle used in medicine, but they respectively contain it in the greatest intensity at different seasons of the year; the cormus (incorrectly called root or solid bulb) having it in perfection about June or July, the flowers in September, and the seeds the following spring. The cormus and seeds are most frequently employed in Britain; but should the proper period (Midsummer) for collecting the cormi be neglected, the flowers may be substituted, though they can only be put to immediate use, as they do not keep well. The cormi are found at various depths under ground; when very deep they are not so good, being the produce of old exhausted plants. Each cormus is about the size of a hazel-nut or walnut, ovate or heart-shaped, consisting of a white fleshy succulent substance, which, when cut across, exhibits roundish plates. It is somewhat flatter on one side, on which also may be discovered a groove, in which is lodged the germ of the flower-stem of the following year. The recent cormus has a nauseous radish-like odour; when dried, no odour; the taste is sweetish-bitter, leaving an acrid sensation in the throat.

The seeds, which should be collected in May, are small, globose, about the size of a grain of millet, of an obscure fawn-colour, opaque, rough, and wrinkled, with a white hilum at the base, very hard, tough, and difficult to reduce to powder. The relative proportions of the constituent ingredients of the cormus differ greatly, according to the season of the year when it is taken up for examination, as Stolze's analyses demonstrate. The active principle of Colchicum was long considered to be the same as that of Veratrum, and hence called Veratria; but Geiger and Hesse have shown that it is different, and have termed it Colchicine. The seeds contain this principle, and likewise some thick oil. Colchicum imparts its active principle partially to water, but more so to acetic acid, proof spirit, and wine. A sirup is sometimes formed of it, but it does not keep well. COLE, COLESEED. [BRASSICA.]

COLEOPTERA (KоλеÓπтEрα), a name first applied by Aristotle Hist. Anim.' i. &c.), and now universally adopted, to designate one of the orders into which Insects are divided, the species of which order are commonly known by the name of Beetles.

Nearly all true Insects, or those Annulose Animals which have six legs, exhibit, in a more or less developed state, four wings, or members, which, although they may not enable the animal to fly, occupy the same situation, and are analogous to those which in many insects are true organs of flight.

These members are modified in various ways to suit the habits of the species or of the groups in general; but in those insects whose habits are of a nature not to require the power of flight they are very seldom entirely wanting, being found either in a rudimentary state, or modified in their structure so as to perform some other office. In those instances where the wings are only rudimentary, we cannot often assign any positive use for them; we can only perceive that the affinities of the individuals exercise an influence in these respectsthat is to say, those species which belong to groups where the individuals generally possess perfect wings, will often possess these members in a rudimentary state, when from their habits they do not require the power of flying. It appeared necessary to make these few general remarks before proceeding to give the distinguishing characters of a Coleopterous Insect, in order that the nature of these characters and the departures from them might be understood; for it is difficult to give a strict definition of any group of animals.

The insects, then, which constitute the order Coleoptera may be characterised as having four wings, of which the two superior are not suited to flight, but form a covering and protection to the two inferior, and are of a hard and horny or parchment-like nature, and when closed, their inner margins, which are straight, touch and form a longitudinal suture (fig. 16, c); the inferior wings, when not in use, are folded transversely under the superior, and are membranous. From this character of having the wings in a sheath, the term Coleoptera was applied, it being composed of the two Greek words koλeós, a sheath, and TTepά, wings. The superior wings, which form the sheath, are generally called elytra.

The principal exceptions to this general rule are as follows:-those beetles which have no under-wings, or have them in a rudimentary state, as in Carabus cancellatus, and those in which the elytra are soldered together at the suture, in which case we believe no under wings are ever found. Another species of Carabus (C. violaceus) and many among the Heteromera afford examples of this exception. There are several beetles in which the elytra do not close at the suture, and in which the under-wings are not protected by them. Such is the case in the genera Sitaris, Ripiphorus, and others, in which the wingcases, or elytra, are somewhat pointed; and in the genus Molorchus, among the Cerambycida, the wing-cases are very short, and the wings are not folded beneath them when at rest. In the Staphylinidæ the wing-cases are also very short, but the under-wings, by a series of folds, are, when not in use, entirely concealed beneath them; and as in this tribe the elytra form a straight suture when closed, the only exception consists in the greater number of folds in the underwings.

Numerous other exceptions might be noticed, but we shall merely mention the genus Meloe, where one elytron partly folds over the other; the families Lampyride and Telephorida, in which the elytra are comparatively soft and flexible; and the glow-worm, the female of which beetle has neither elytra nor wings.

The larvæ of Coleopterous Insects are generally composed of thirteen distinct segments, the head included. They are almost always of an elongate cylindrical or slightly depressed form; the body is often soft and fleshy, and of a white colour: in these the head is always of a firmer texture, being of a horny nature. The principal parts of the mouth are the same, as to number, as in the perfect insect, although the parts are (as far as our observations go) always differently formed. The head is furnished with two antennæ, which are generally minute, and composed of four joints; and ocelli, or simple eyes, are, on each side, situated near the base of the antenna. The body is furnished with six legs, which are attached to the first three segments, or those next the head, a pair to each: the legs are small and usually terminated by a simple claw. Sometimes, in addition to the ordinary legs, the larva is furnished with false legs (often termed pro-legs); these are fleshy tubercles which the animal can protrude at pleasure, and are used to propel the body. Some larvæ have only two of these pro-legs, which are attached to the apex of the terminal segment of the abdomen, or placed beneath that segment; and in the larva of the species of Cerambycide each segment of the body is thickened in the middle both above and below: these parts the animal has the power of protruding considerably, by which means it is enabled to thrust itself forwards or backwards in the holes in the trunks or boughs of trees which are formed by its feeding upon the wood.

The larva of groups (generally believed to be natural) very closely resemble each other, though those of different groups are sufficiently distinct; hence a knowledge of the larvæ is of great use in determining the natural affinities of species when their families or sections are not well ascertained.

We select as an illustration of the principal characters of a Coleop terous larva, that of one of the Lamellicornes, a group which comprises the common Cockchafer, and where the larvæ generally, if not always, have their body bent under at the apex.