Part 13
CENTURY (from Lat. _centuria_, a division of a hundred men), the name for a unit in the Roman army, originally amounting to one hundred men, and for one of the divisions into which the Roman people was separated for voting purposes (see COMITIA). The word is applied to any group of one hundred, and more particularly to a period of a hundred years, and to the successive periods of a hundred years, dating before or after the birth of Christ. The "Century-plant" is a name given to the Agave (q.v.), or American aloe, from the supposition that it flowered once only in every hundred years.
CEOS (Gr. [Greek: Keôs], mod. _Zea_ or _Tzia_), an island in the Aegean Sea, belonging to the group of the Cyclades and the eparchy of Syra, 14 m. off the coast of Attica. Its greatest length is about 15 m. and its breadth about 8 m. It rises gradually towards the centre, where it culminates in Mount Elias, 1864 ft. high. Among its natural productions are lemons, citrons, olives, wine and honey; it also exports a considerable quantity of valonia. There were formerly four towns of some importance in the island:--Iulis, about 3 m. from the north-west shore; Coressia, the harbour of Iulis, with a temple of Apollo Smintheus in the neighbourhood; Carthaea, in the south-east, with a temple of Apollo; and Poieëssa, in the south-west. Of these Iulis is represented by the town of Zea, and Carthaea by the village of 'S tais Polais; traces of the other two can still be made out. Iulis was the birthplace of the lyric poets Simonides and Bacchylides, the philosophers Prodicus and Ariston, and the physician Erasistratus; the excellence of its laws was so generally recognized that the title of Cean Laws passed into a proverb. One of them forbade a citizen to protract his life beyond sixty years. The people of Ceos fought on the Greek side at Artemisium and Salamis; they joined the Delian League and also the later Athenian alliance in 377 B.C. They revolted in 363-362, but were reduced again, and the Athenians established a monopoly of the ruddle, or red earth, which was one of the most valuable products of the island. In A.D. 1207 it was divided between four Italian adventurers; after forming part of the duchy of Naxos in 1537, it passed under Turkish rule in 1566. Silver coins of Carthaea and Coressia have been found dating from the 6th century B.C. (see NUMISMATICS: _Greek_, "Cyclades and Sporades"). The present population of the island is about 4000, of which the capital has about 2000.
See Pridik, _De Cei Insulae rebus_ (1892). (E. Gr.)
CEPHALIC INDEX, the term in use by anthropologists to express the percentage of breadth to length in any skull. The principle employed by Retzius is to take the longer diameter of a skull, the antero-posterior diameter, as 100; if the shorter or transverse diameter falls below 80 the skull may be classed as long (dolichocephalic), while if it exceeds 80 the skull is broad (brachycephalic) (see CRANIOMETRY).
CEPHALONIA (Ital. _Cefalonia_, ancient and modern official Greek _Cephallenia_, [Greek: Kephallênia]), an island belonging to the kingdom of Greece, and the largest of those known as the Ionian Islands, situated on the west side of the mainland, almost directly opposite the Gulf of Corinth. The name was traditionally derived from Cephalus, the Attic hero who was regarded as having colonized the island. The tradition, which is repeated by Aristotle, is probably due solely to the similarity of the names (see J.G. Frazer, _Pausanias_, i. 37, 6 note). Pop. (1907) 71,235. Its extreme length is 31 m., and its breadth varies from about 20 m. in the southern portion to 3 m. or less in the projecting part, which runs parallel with the island of Ithaca, at a distance of about 4 m. across the strait of Guiscardo or Viscaro. The whole island, with its area of 348 English sq. m., is covered with rocky hills of varying elevation, the main range running from north-west to south-east. The ancient Mount Aenos, now Elato, Monte Negro, or the Black Mountain (5315 ft.), frequently retains the snow for several months. It is not only the loftiest part of the sierra, but also the highest land in the whole Ionian group. The name "Black" was given from the darkness of the pine woods which still constitute the most striking feature in Cephalonian scenery, although their extent has been greatly curtailed by fire. The summit is called Megálo Sorós. The island is ill supplied with fresh water; there are few permanent streams except the Rakli, and springs are apt to fail in dry summers. In the western part of the island a gulf runs up from the south, a distance of about 7 m.; on its east side stands the chief town Argostoli, with about 10,000 inhabitants, and on its west side the rival city of Lixouri, with 6000. About a mile west of the town are the curious sea mills; a stream of sea water running down a chasm in the shore is made to turn the wheels. About 5 m. from Argostoli is the castle of St George, a building of Venetian origin, and the strongest fortification in the island. On an eminence east-south-east of Argostoli are the ruins of the ancient Cranii, and Lixouri is close to or upon those of Pale; while on the other side of the island are the remains of Samos on the bay of the same name, of Proni or Pronni, farther south above the vale of Rakli and its blossoming oleanders, and of an unknown city near the village of Scala. The ruins of this city include Roman baths, a brick-built temple, rock-cut tombs, and tessellated pavements; and Cranii, Proni and Samos are remarkable for stretches of Cyclopean and Hellenic walls, partly of the most irregular construction, and partly preserving almost unimpaired the results of the most perfect skill. The inhabitants of Cephalonia have all along been extremely active; and no slight amount of toil has been expended in the construction of terraces on the steep sides of the hills. Owing to the thinness of the population, however, but a small proportion of the soil is under cultivation, and the quantity of grain grown in the island is comparatively meagre. The staple is the currant, in the production of which the island surpasses Zante. The fruit is smaller than that of the Morea, and has a peculiar flavour; it finds a market mainly in Holland, Belgium and Germany. The grape vine also is grown, and the manufacture of wine is a rising industry. The olive crop is of considerable importance, and the culture of cotton in the low grounds has been successfully attempted. Manufactures are few and undeveloped, but lace from the aloe fibre, Turkey carpets and basket-work are produced by the villagers, and boats are built at both the principal towns. Of all the seven Ionian islands Cephalonia and Zante are most purely Greek, and the inhabitants display great mental activity.
In the Homeric poems Cephalonia is generally supposed to be mentioned under the name of Same, and its inhabitants, among the subjects of Ulysses, to be designated Cephallenes (see, however, under ITHACA). In the Persian War they took but little part; in the Peloponnesian they sided with the Athenians. The town of Pale was vainly besieged by Philip of Macedon in 218 B.C., because it had supported the Aetolian cause. In 189 B.C. all the cities surrendered to the Romans, but Same afterwards revolted, and was only reduced after a siege of four months. The island was presented by Hadrian to Athens, but it appears again at a later date as "free and autonomous." After the division of the Roman empire, it continued attached to Byzantium till 1082, when it was captured by Robert Guiscard, who died, however, before he could repress the revolt of 1085. In 1204 it was assigned to Gaius, prince of Tarentum, who accepted the protection of Venice in 1215; and after 1225 it was held along with Santa Maura and Zante by a succession of five counts of the Tocco family at Naples. Formally made over to Venice in 1350 by the prince of Tarentum, it was afterwards captured by the Turks in 1479; but the Hispanico-Venetian fleet under Benedetto Pessaro and Gonsalvo of Cordova effected their expulsion in 1500, and the island continued in Venetian possession till the fall of the republic. For some time it was administered for the French government, but in 1809 it was taken by the British under Cuthbert, Lord Collingwood. Till 1813 it was in the hands of Major de Bosset, a Swiss in the British service, who displayed an industry and energy in the repression of injustice and development of civilization only outdone by the despotic vigour of Sir Charles Napier, who held the same office for the nine years from 1818 to 1827. During the British protectorate the island made undoubted advances in material prosperity, but was several times the scene of political disturbances. It retained longer than the sister islands traces of feudal influence exerted by the landed proprietors, but has been gradually becoming more democratic. Under the Venetians it was divided into eight districts, and an elaborate system of police was in force; since its annexation to Greece it has been broken up into twenty demarchies, each with its separate jurisdiction and revenues, and the police system has been abolished.
AUTHORITIES.--A special treatise on the antiquities of Cephalonia was written by Petrus Maurocenus. See Holland's _Travels_ (1815); Ansted's _Ionian Islands_ (1863); Viscount Kirkwall's _Four Years in Ionian Islands_ (1864); Wiebel's _Die Insel Kephalonia_; parliamentary papers. Riemann, _Recherches archéologiques sur les Iles Ioniennes_ (Paris, 1879-1880); Partsch, _Kephallenia und Ithaka_ (1890); see also CORFU; IONIAN ISLANDS. (E. Gr.)
CEPHALOPODA, the fifth of the classes into which the zoological phylum Mollusca is divided (see MOLLUSCA). The Cephalopoda are mainly characterized by the concrescence of the foot and head. The foot grows forward on each side so as to surround the mouth, the two upgrowths meeting on the dorsal side of the head--whence the name Cephalopoda. The perioral portion of the foot is drawn out into paired arm-like processes; these may be beset with sheathed tentacles or with suckers or hooks, or both. The epipodia are expanded into a pair of muscular lobes right and left, which are bent round towards one another so that their free margins meet and constitute a short tube--the siphon or funnel. The hind-foot is either very small or absent. A distinctive feature of the Cephalopoda is their bilateral symmetry and the absence of anything like the torsion of the visceral mass seen in the Anisopleurous Gastropoda.
The anus, although it may be a little displaced from the median line, is approximately median and posterior. The mantle-skirt is deeply produced posteriorly, forming a large sub-pallial chamber around the anus. By the side of the anus are placed the single or paired apertures of the nephridia, the genital apertures (paired only in _Nautilus_, in female Octopoda, female _Ommatostrephes_ and male _Eledone_), and the paired ctenidia. The visceral hump or dome is elevated, and may be very much elongated in a direction almost at right angles to the primary horizontal axis of the foot.
A shell is frequently, but not invariably, secreted on the visceral hump and mantle-skirt. The shell is usually light in substance or lightened by air-chambers in correlation with the free-swimming habits of the Cephalopoda. It may be external or internal, that is, enclosed in folds of the mantle. Very numerous minute pigmented sacs, capable of expansion and contraction, and known as chromatophores, are usually present in the integument. The sexes are separate.
The ctenidia are well developed as paired gill-plumes, serving as the efficient branchial organs (figs. 4, 24),
The vascular system is very highly developed; the heart consists of a pair of auricles and a ventricle (figs. 12, 28). Branchial hearts are formed on the afferent vessels of the branchiae. It is not known to what extent the minute subdivision of the arteries extends, or whether there is a true capillary system.
The pericardium is extended so as to form a very large sac, passing among the viscera dorsalwards and sometimes containing the ovary or testis--the viscero-pericardial sac--which opens to the exterior either directly or through the renal organs. It has no connexion with the vascular system. The renal organs are always paired sacs, the walls of which invest the branchial afferent vessels (figs. 28, 29). They open each by a pore into the viscero-pericardial sac, except in _Nautilus_. The anal aperture is median and raised on a papilla. Jaws (fig. 6, e) and a radula (fig. 9) are well developed. The jaws have the form of powerful beaks, either horny or calcified (_Nautilus_), and are capable of inflicting severe wounds.
Cerebral, pleural and pedal ganglia are present, but the connectives are shortened and the ganglia concentrated and fused in the cephalic region. Large special ganglia (optic, stellate and supra-buccal) are developed. Sense-organs are highly developed; the eye exhibits a very special elaboration of structure in the Dibranchiata, and a remarkable archaic form in the nautilus. Otocysts are present in all. The typical osphradium is not present, except in _Nautilus_, but other organs are present in the cephalic region, to which an olfactory function is ascribed both in _Nautilus_ and in the other Cephalopoda.
Hermaphroditism is unknown in Cephalopoda; male and female individuals always being differentiated. The genital aperture and duct is sometimes single, when it is the left; sometimes the typical pair is developed right and left of the anus. The males of nearly all Cephalopoda have been shown to be characterized by a peculiar modification of the arm-like processes or lobes of the fore-foot, connected with the copulative function. The term hectocotylization is applied to this modification (see figs. 6, 24). Elaborate spermatophores or sperm-ropes are formed by all Cephalopoda, and very usually the female possesses special capsule-forming and nidamental glands for providing envelopes to the eggs (fig. 4, g.n.). The egg is large, and the development is much modified by the presence of an excessive amount of food-material diffused in the protoplasm of the egg-cell. Trochosphere and veliger stages of development are consequently not recognizable.
The Cephalopoda are divisible into two orders, Tetrabranchiata and Dibranchiata, the names of which (due to Sir R. Owen) describe the number of gill-plumes present; but in fact there are several characters, of as great importance as those derived from the gills, by which the members of these two orders are separated from one another.
ORDER 1. TETRABRANCHIATA (= Schizosiphona, Tentaculifera).
_Characters_.--The inrolled lateral margins of the epipodia are not fused, but form a siphon by apposition (fig. 4). The circumoral lobes of the fore-foot carry numerous retractile tentacles, not suckers (fig. 6). There are two pairs of ctenidial gills (hence Tetrabranchiata), and two pairs of renal organs, consequently four renal apertures (fig. 4). The viscero-pericardial chamber opens by two independent apertures to the exterior, and not into the renal sacs. There are two oviducts (right and left) in the female, and two sperm-ducts in the male, the left duct in both sexes being rudimentary. A large external shell, either coiled or straight, is present, and is not enclosed by reflections of the mantle-skirt. The shell consists of a series of chambers, the last-formed of which is occupied by the body of the animal, the hinder ones (successively deserted) containing gas (fig. 1). The pair of cephalic eyes are hollow chambers (fig. 14. A), opening to the exterior by minute orifices (pin-hole camera), and devoid of refractive structures. A pair of osphradia are present at the base of the gills (fig. 4, _olf_). Salivary glands are wanting. An ink-sac is _not_ present. Branchial hearts are _not_ developed on the branchial afferent vessels.
[Illustration: FIG. 1.--Lateral view of the female Pearly Nautilus, contracted by spirit and lying in its shell, the right half of which is cut away (from Gegenbaur, after Owen).
a, Visceral hump.
b, Portion of the free edge of the mantle-skirt reflected on to the shell,--the edge of the mantle-skirt can be traced downwards and forwards around the base of the mid-foot or siphon i.
l, l, Superficial origin of the retractor muscle of the mid-foot (siphon), more or less firmly attached to the shell, of which a small piece (s) is seen between the letters l, l.
s, (farther back) points to the siphuncular pedicle, which is broken off short and not continued, as in the perfect state, through the whole length of the siphuncle of the shell, also marked s and s'.
o, points to the right eye.
t, is placed near the extremities of the contracted tentacles of the outer or annular lobe of the fore-foot--the jointed tentacles are seen protruding a little from their long cylindrical sheaths.
v, The dorsal "hood" formed by an enlargement in this region of the annular lobe of the fore-foot (m in figs. 2, 3).
V, A swelling of the mantle-skirt, indicating the position on its inner face of the nidamental gland (see fig. 4, g.n.).]
_Visceral Hump and Shell._--The visceral hump of _Nautilus_ (if we exclude from consideration the fine siphuncular pedicle which it trails, as it were, behind it) is very little, if at all, affected by the coiled form of the shell which it carries, since the animal always slips forward in the shell as it grows, and inhabits a chamber which is practically cylindrical (fig. 1). Were the deserted chambers thrown off instead of being accumulated behind the inhabited chamber as a coiled series of air-chambers, we should have a more correct indication in the shell of the extent and form of the animal's body. Amongst Gastropods it is not very unusual to find the animal slipping forward in its shell as growth advances and leaving an unoccupied chamber in the apex of the shell. This may indeed become shut off from the occupied cavity by a transverse septum, and a series of such septa may be formed, but in no Gastropod are these apical chambers known to contain a gas during the life of the animal in whose shell they occur. A further peculiarity of the nautilus shell and of that of the allied extinct _Ammonites_, _Scaphites_, _Orthoceras_, &c., and of the living _Spirula_, is that the series of deserted air-chambers is traversed by a cord-like pedicle extending from the centro-dorsal area of the visceral hump to the smallest and first-formed chamber of the series. No structure comparable to this siphuncular pedicle is known in any other Mollusca. The siphuncle does not communicate with the coelomic cavity; it is a simple vascular process of the mantle, whose cavity consists of a venous sinus, and whose wall contains a ramification of the pallial artery. There appears to be no doubt that the deserted chambers of the nautilus shell contain in the healthy living animal a gas which serves to lessen the specific gravity of the whole organism. This gas is said to be of the same composition as the atmosphere, with a larger proportion of nitrogen. With regard to its origin we have only conjectures. Each septum shutting off an air-containing chamber is formed during a period of quiescence, probably after the reproductive act, when the visceral mass of the nautilus may be slightly shrunk, and gas is secreted from the dorsal integument so as to fill up the space previously occupied by the animal. A certain stage is reached in the growth of the animal when no new chambers are formed. The whole process of the loosening of the animal in its chamber and of its slipping forward when a new septum is formed, as well as the mode in which the air-chambers may be used as a hydrostatic apparatus, and the relation to this use, if any, of the siphuncular pedicle, is involved in obscurity, and is the subject of much ingenious speculation. In connexion with the secretion of gas by the animal, besides the parallel cases ranging from the protozoon _Arcella_ to the physoclistic fishes, from the hydroid _Siphonophora_ to the insect-larva _Corethra_, we have the identical phenomenon observed in the closely allied _Sepia_ when recently hatched. Here, in the pores of the internal rudimentary shell, gas is observable, which has necessarily been liberated by the tissues which secrete the shell, and not derived from any external source (Huxley).
The coiled shell of _Nautilus_, and of the majority of extinct Tetrabranchiata, is peculiar in its relation to the body of the animal, inasmuch as the curvature of the coil proceeding from the centro-dorsal area is towards the head or forwards, instead of away from the head and backwards as in other discoid coiled shells such as _Planorbis_; the coil is in fact absolutely reversed in the two cases. Such a shell is said to be exogastric. But in some extinct forms, e.g. _Phragmoceras_, _Cyrtoceras_, _Ptenoceras_, the shell is coiled towards the ventral side, when it is termed endogastric. Amongst the extinct allies of the nautilus (Tetrabranchiata) we find shells of a variety of shapes, open coils such as _Scaphites_, leading on to perfectly cylindrical shells with chamber succeeding chamber in a straight line (_Orthoceras_), whence again we may pass to the corkscrew spires formed by the shell of _Turrilites_. In some extinct genera, e.g. _Gomphoceras_, among the Nautiloidea the aperture of the shell is contracted and the edge of the aperture is lobed. In these cases the animal was probably able only to protrude its appendages and not its whole head. The ventral part of the aperture corresponding to the funnel is separated from the dorsal part by a constriction. Hence it is possible to distinguish the ventral and dorsal sides of the shell and to decide whether it was exogastric or endogastric. The direction of the coil of the shell cannot be determined by the position of the siphuncle, which traverses the septa centrally, ventrally or dorsally. Contracted shell apertures occur also in Ammonitoidea, the condition reaching an extreme in _Morphoceras_, where the original aperture is subdivided by the ingrowth of the sides, so that only five small separate apertures remain. Of these the central probably corresponded to the mouth, two lateral to the eyes, and the remaining two to the pedal appendages.
_Head, Foot, Mantle-skirt and Sub-pallial Chamber._--In the pearly nautilus the ovoid visceral hump is completely encircled by the free flap of integument known as mantle-skirt (figs. 2, 3, d, e). In the antero-dorsal region this flap is enlarged so as to be reflected a little over the coil of the shell which rests on it. In the postero-ventral region the flap is deepest, forming an extensive sub-pallial chamber, at the entrance of which e is placed in fig. 3. A view of the interior of the sub-pallial chamber, as seen when the mantle-skirt is retroverted and the observer faces in the direction indicated by the reference line passing from e in fig. 3, is given in fig. 4. With this should be compared the similar view of the sub-pallial chamber of the Dibranchiate _Sepia_. It should be noted as a difference between _Nautilus_ and the Dibranchiates that in the former the nidamental gland (in the female) lies on that surface of the pallial chamber formed by the dependent mantle-flap (fig. 4, g.n.; fig. 1, V), whilst in the latter it lies on the surface formed by the body-wall; in fact in the former the base of the fold forming the mantle-skirt comprises in its area a part of what is unreflected visceral hump in the latter.
[Illustration: FIG. 2.--Spirit specimen of female Pearly Nautilus, removed from its shell, and seen from the antero-dorsal aspect (drawn from nature by A.G. Bourne).
m, The dorsal "hood" formed by the enlargement of the outer or annular lobe of the fore-foot, and corresponding to the sheaths of two tentacles (g, g in fig. 6).