formula CN3O3Hs, and obtained by the dry distillation of uric acid. It is a polymer of cyanic acid, CNOH, and may be obtained, along with another polymer of unknown molecular weight called cyamelide, by the spontaneous polymerization of cyanic acid. To obtain it in this way, potassium cyanate, CNOK, is treated with hydrochloric acid in the presence of ether, the mixture being well shaken. Potassium chloride and cyanic acid are formed, the latter polymerizing at once into the two compounds mentioned above, the cyanuric acid that is formed being taken up by the ether, from which it may afterward be recovered by evaporation. Cyanuric acid forms colorless efflorescent crystals which contain two molecules of water when deposited from solution in water. The hydrous crystals have the form of rhombic prisms; but anhydrous crystals, octahedral in form, are also known. Cyanuric acid dissolves in hot nitric, hydrochloric, or sulphuric acid, there being no decomposition unless the action is prolonged. When heated it becomes converted into cyanic acid, this reaction being one of the tests that are employed for its detection.

Cyath'ea, a genus of arborescent ferns, order Polypodiacea, characterized by having the spores, which are borne on the back of the frond, enclosed in a cup-shaped indusium. There are many species scattered over the tropical regions of the world. C. medullaris is a fine New Zealand species of comparatively hardy character. The soft, pulpy, medullary substance in the centre of the trunk is an article of food somewhat resembling sago. This species and the South African C. dealbata are cultivated as ornamental plants. C. arborea is a West Indian species.

Cyathom'eter, a recently invented apparaus for determining the level and volume of liquids in closed vessels. It is adapted to bottles and to stationary vessels and is designed especially to prevent fraud in the retail trade in valuable liquids. The apparatus consists of a glass tube fluted internally, of a glass telltale or float provided with two straight springs, and of a solid ball. The tube is suspended in a bottle arranged for the purpose at the time of manufacture, from a band of twisted wires of inoxidizable metal, the extremities of which, after passing through the neck, are united and provided with a lead seal. When a full bottle is provided with the cyathometer, the telltale is at the upper part of the tube. If a certain portion of the contents be poured out, the levels of the bottle and tube will descend together and the telltale will constantly follow them. If, on the contrary, any quantity whatever of liquid be added, the levels will rise, but the telltale, held by its springs, which are braced against the flutings of the tube, will remain where it was before the addition. It is therefore submerged and marks the precise point where the addition or substitution began. Any fraud will be revealed by the telltale at the very moment at which it occurred. When the cyathometer is adapted to vats, tanks, casks, etc., the telltale consists of a float and sleeve placed in contact, and each carrying three or four springs pointing in contrary directions, those of the float engaging with the sleeve. The apparatus lends itself also to the control of movable receptacles of large capacity.

Cybele, sĭb'ě-lē or sib-ē'lē, a goddess of the Phrygians, like Isis, the symbol of the moon, and what is nearly connected with this, of the fruitfulness of the earth, for which reason she is confounded with Rhea, whose worship originated in Crete, and in whom personified nature was revered. According to Diodorus Cybele was the daughter of the Phrygian king Mæon and his wife Dindyma. At her birth her father, vexed that the child was not a boy, exposed her upon Mount Cybelus, where she was nursed by lions and panthers, and afterward found and brought up by the wives of the herdsmen. She invented fifes and drums, with which she cured the diseases of beasts and children, became intimate with Marsyas, and feli violently in love with Atys. She was afterward recognized and received by her parents. Her father discovering her love for Atys had him seized and executed, and left his body unburied. The grief of Cybele on this occasion deranged her understanding and she began a long search for Atys. In art her original statue was nothing but a dark quadrangular stone. Afterward she was represented as a matron, with a mural crown on her head, in reference to the improved condition of men arising from agriculture and their union into cities. A common attribute of the goddess is the veil about her head, which refers to the mysterious and incomprehensible in nature. In her right hand she often holds a staff, as an emblem of her power, and in her left a Phrygian drum. Sometimes a few ears of corn stand near her. The hand, and the crescent of the moon in her left. sun also is sometimes represented in her right We sometimes see her in a chariot drawn by lions; or else she sits upon a lion, and, as omnipotent nature, she holds a thunderbolt; or a lion lies near her. These symbols are all representations of her dominion and of the introduction of civilization by her means in the period of barbarism.

=

or

Cycads (from Cycas Neo-Lat. nom. pl. of Gr. κύκας, the original name of the African cocoa-palm), a group of naked-seeded The gymnospermous plants, the cycadales. existing cycads are an ornate remnant of an ancient and once widely extended series of forms, their nearest living relative being the gingko or maidenhair-tree. The large pith of the thick palm-like trunk of certain species is the source of the sago starch of commerce, whence the common name, sago-palm.

The cycads are a primitive and composite type with the wood structure of pines (and Cordaites), certain frond and other characters of ferns, and the outward habit of palms. As in the latter, the stem elongates by the slow growth of a terminal bud, with the unfolding of successive crowns of leaves or fronds spirally arranged in close order. As the leaves wilt down, there is formed from their bases an outer more or less persistent armor, which gives the stem its very characteristic appearance. For trunk-forming plants the cycads are mostly small or even pygmean. They include tuberous to columnar forms, and vary in size from underground trunks a few centimetres in diameter with fronds no more than a decimetre long to the tallest species of Cycas (Fig. 2, plate), which may reach a height of 20 metres. The most robust trunks reach rarely a metre in

mentous, being largely made up of freely branching adventitious roots.

The leaves or fronds are usually of two kinds, scale and foliage. There are also the fertile or carpellary leaves of Cycas. All appear in terminal rosettes in the order named, scale, foliage, and when present, carpellary leaves. The scale leaves are dry and aborted foliage leaves, and are present in all but certain species of Macrozamia. The elliptical to acuminate foliage leaves are bipinnate in Bowenia, and pinnate in all the other genera. Prefoliation is direct in Dion and Macrozamia. In Cycas the richis is straight, but the pinnules are circinnately rolled like those of ferns. Conversely in several other genera the pinnules lie straight along the once deflexed rachis. The pinnules, various types of which are shown (Fig. 4, plate), are of hard to leathery texture, much varying size and form, and dichotomous venation, except in Cycas, which has a single midvein. Those of Stangeria are very fern-like. The anatomical structure is much as in certain conifers and the extinct Cordaites.

FIG. 5.- Zamia floridana DC.

X2. November stage of growth. Slightly bifurcate trunk bearing three staminate cones on the right and two on the left. Trunk shown with leaves removed and as if cut away on the ground level. (From Wieland.)

Fructification.-The living cycads are all diœcious. The microsporophylls are always organized into cones which may vary from a few centimetres long to enormous forms 80 centimetres long by 15 or more centimetres in diameter, bearing as many as 600 microsporophylls, these being the most massive to be seen in seed plants. Several forms of microsporophylls are shown isolated (Fig. 6, plate), and staminate cones (Fig. 5) as borne on the parent plant. The sporangia are borne on the under side of the sporophyll and are structurally much like those of Angiopteris among the Marattiacea. In certain genera there is obscure grouping into sori (Fig. 6, plate, A, B, and C).

an

The ovules, which are the largest known in the vegetable kingdom, are in the genus Cycas,

doubtless the most primitive type among recent phanerogams, borne on the margins of modified leaves, emergent in regular series like the ordinary foliage leaves. In the other genera the megasporophylls each bear but a single pair of ovules, and are organized into a large terminal cone, or several such cones. See illustration of principal types of megasporophylls (Fig. 7, plate). The ovulate and staminate strobili agree in general form, and in the terminal or nearly terminal position in which they are borne in all the genera. After the production of cones in plants of either sex the stem continues its growth as a sympode.

Fecundation.- Among the various primitive characters of the cycads going to prove their descent from homosporous tree-ferns, easily the

most recondite is the oc

currence of motile multiciliate male cells of the coiled type characteristic of all the Pteridophytes except the club mosses. Spermatozoids are doubtless common to all the cycadales and are present in gingko, but are not known in any other phanerogams. The pollen grains are drawn through the micropylar tube into the pollen chamber (by suction), after which the pollen tube ruptures the exine and enters the nuccellar tissue, where it may branch. Meanwhile spermatozoids FIG. 8.-Zamia flori. form from the generative dana DC. End cells and, after the rupture of mature pol- of the pollen tube, swim aclen tube after tively to the archegonium formation of the cilia of through a liquid medium afthe two sperma- forded in part by the tube, tozoids and just and probably also by extrubefore these pull sion from the egg-cell. The mature spermatozoids are archegonia. X the largest known in any (From plant (or animal), at least in Zamia floridana. In this species they are visible to the naked eye, and have been studied alive in sugar solutions. They are of nearly spherical top-shape, with a ciliferous spiral running from the apex to the middle region, and motion is mainly by means of their cilia, but there is also amoeboid motion of the spiral end (see Figs. 8 and 9).

apart to swim free to the

50. Webber.)

FIG. 9.- Zamia flori

dana DC. Mature spermatozoid while swimming free. X 100. (From Webber.)

From this most primitive form of fecundation known in flowering plants, it seems evident that not until the later stages of plant evolution did the pollen tube begin to serve as a direct means of transfer of the male cells as in other phanerogams. The seed-coats instead of being entirely woody, as in the conifers, develop a lignified inner and a pulpy outer layer. In the conebearing forms appression faces form, but in Cycas the free seeds look much like plums, those of C. circinalis reaching the size of goose

cal and sub-tropical regions. There are four indigenous Occidental genera as follows: Zamia, with 37 species, ranges over the mainland from Florida, where two species occur, to Brazil, and also over the West Indies; Ceratozamia, with six species, and Dion with two, are mainly Mexican and Central American; while the monotypic Microcycas is Cuban. In the Orient five genera occur: Cycas, with 23 species, is the most notable, and ranges over Australia, the East Indies, and Japan; Macrozamia, with 12 species, and the monotypic Bowenia are both strictly Australasian; while Encephalartos with 20 species, and the ditypic Stangeria are African.

FIG.

Fossil Cycads.-As in the case of various unique types in the existing flora, the present isolation of the cycads is connected with a history of great extent in space and time. The living forms are only two side branches of a varied cycadalean group, of which the Cycadacea are the more ancient, characteristic leaves of the Cycas type having already been present in the Carboniferous limestone.

12. Cycadeoidea Wieland through an ovulate strobi of the Yale collection. leaf bases shown partly arises from the axil of bundle supply of the le duncle is shown, also th X (From Wieland.)

Bennettitea.- In additi plants are known, from the are but distantly related Among these the Bennett terest from an evolutionar may represent a fifth grea nosperms, the Bennettital prints of leaves, fruits, an this group are known wit Trias of southern Swed type seems to have exte globe in Jurassic time. trunks with microscopic have been found in consid European Jurassic and Cret land, and more recently in gion in uppermost Jurassi Cretaceous strata. The A clude both low-branching t and columnar forms, and ar known of ancient plants.

The Zamiacea were already present in the Jurassic, during which period cycadaceous types apparently culminated in both variety and extent.- Noteworthy is the occurrence of an asso

structure, as determined from the silicified derived. Surro crowns of young leaves discovered by Wieland hypogynous sta (Fig. 11), a close agreement. But in fructification they are entirely different.

The ovulate cone is a bract-enveloped spherical to pear-shaped and small to full pear-sized body, terminating a short axillary shoot emerging laterally on the trunk from among the old leaf-bases and ramentum, as here illustrated (Fig. 12). In structure this fruit is wholly unique. The end of the peduncle expands into a fleshy convex or conical receptacle, on which is inserted, as if fused into a single body, a series of sterile scales, and fertile sporophylls. Each of the latter bears at its end a single seed with the elongate micropylar tube directed outward from between the expanded tips of the non-fertile interstitial scales, which are of such

Wislandi Longitudinal section the strobilus borne on trunk 393 Exteriorly are the old ection. The fruit partly cut away. axi of that to the right. The the leaf bases and thick pe also the exterior hairy bracts. ieland.)

addition many cycad-like om the Cretaceous on, which elated to the living forms Bennettitea are of deep inutionary point of view, and th great group of the gymnettitales. Interesting im its, and stems belonging to wn with certainty from the Sweden, and the general e extended quite over the time. Beautifully silicified oscopic structure preserved considerable number in the nd Cretaceous, also in Maryently in the Black Hills re Jurassic or else lowermost The American specimens inching trunks (Fig. 10, plate) and are now among the best ants. These trunks are usu

FIG. 13.- Cycadeoidea. Longitudinal section through bisporangiate strobilus. Diagrammatic. At the centre is the apical ovulate cone closely invested by a zone of short-stalked ovules and interseminal scales. On the left is a single once pinnate and yet folded fertile frond of the staminate disk. the right a similar synangia-bearing frond is arbitrarily shown in an expanded position. riorly are the imbricating hairy bracts. About 34 natural size. (From Wieland.)

On

Exte

evenly decreasing length from the centre of the receptacle to its periphery, as to thus form a continuous outer covering of the fruit. Basally there are sterile organs only. The ellipsoidal seeds are about three millimetres long, orthotropous, exalbuminous or nearly so, and dicotyledonous. Perhaps the nearest approach in general form among plants now living to the present type of fructification is to be seen in the peculiar ovulate strobilus of certain species of the monocotyl Pandanus, rather than in any known cycads whatsoever. The staminate fructification is even more noteworthy (Fig. 13). It is bisporangiate, and also a lateral bract

FIG. 14.- Cycade of a transv sporangiate In the cent heavy walled by a thin-wa sporangial the synangi limited by t pollen grain on the inne cell in thic adjacent lo several cells opposed inn usually spli angia, and cells when instances. The tips of the figur right angles At the lower versely cut (From Wiel

species of from fronds with ba having been on fully expanded centimetres in objects of grea staminate from form. The p fuller detail ( nearly identica spore-bearing s