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salem were founded the two famous orders of the the exception of the Mosque of Omar), Jaffa, Beth Knights Hospitallers of St John and the Knights lehem, and Nazareth were ceded to Frederick, who, Templars.

after being crowned king of Jerusalem, returned Second Crusade.-In 1144 the principality of to Europe, leaving his new possessions in a state of Edessa was conquered by the Emir of Mosul, and tranquillity. Frederick, however, who had been the Christians slaughtered. His son, Noureddin, excommunicated by Gregory IX. for his tardiness advanced to destroy the Latin kingdoms of Syria in embarking in this crusade, was denounced in the and Palestine. Europe once more trembled with most violent language by the same pope for having excitement. A second crusade was preached by thus made terms with the infidel. the famous St Bernard, abbot of Clairvaux, in Sixth Crusade.-In 1244 the Khorasmians, driven Champagne; and early in 1147 two enormous from Tartary by Genghis Khan, burst into Syria, armies, under the command of Louis VII., king and made themselves masters of Jerusalem. This of France, and Conrad III., emperor of Germany, was made, by Pope Innocent IV., the occasion for marched for the Holy Land. Their united another crusade ; and in 1249 Louis IX. (St Louis) numbers were estimated at 1,200,000 fighting | of France headed an expedition against Egypt, men. The expedition, nevertheless, proved a which was now regarded as the key of the Holy total failure. The Greek emperor, Manuel Com. Land. The expedition was an utter failure. Louis nenus, was hostile; and through the treachery was defeated and taken prisoner by the sultan, and of his emissaries, the army of Conrad was all but obtained his liberty only on the payment of a heavy destroyed by the Turks near Iconium, while that ransom. of Lonis was wrecked in the defiles of the Pisidian Seventh Crusade. This also was primarily under. Mountains. After a vain attempt to reduce taken by St Louis, but he having died at Tunis Damascus, the relics of this mighty host returned (where he had gone in the hope of baptising its to Europe.

king) in 1270, on his way to Palestine, Prince Third Crusade.—The death-blow, however, to Edward of England, afterwards Edward I., who the kingdom of Jerusalem, and the power of the had originally intended to place himself under the crusaders, was given, not by Noureddin, but by command of St Louis, marched direct for Palestine, Salah-Eddin, commonly called Saladin, a young where his rank and reputation in arms gathered Kurdish chief, who had made himself sultan of round him all who were willing to fight for the Egypt, and who aspired to the suzerainty of the cross. Nothing of consequence, however, was Mohammedan world. He invaded Palestine, took accomplished ; and Edward soon returned to Eng. town after town, and finally, in October 1187, land, the last of the crusaders. Acre, Antioch, compelled Jerusalem itself to capitulate, after a and Tripoli still continued in the possession of the siege of fourteen days. The news of this led to Christians, and were defended for some time by the a third crusade, the chiefs of which were Frederick Templars and other military knights; but in 1291 1. (Barbarossa), emperor of Germany; Philippe Acre capitulated, the other towns soon followed its Auguste, king of France, and Richard Cæur-de- example, and the knights were glad to quit the Lion, king of England. Barbarossa took the country, and disperse themselves over Europe in field first in the spring of 1189, but lost his life by quest of new employment, leaving Palestine in the fever caught from bathing in the Orontes. His undisturbed possession of the Saracens. army, much reduced, joined the forces of the other Besides the great expeditions above enumerated, two monarchs before Acre, which important city there were many others on a lesser scale. These, was immediately besieged. In vain did Saladin however, from the unimportance of their results, attempt to relieve the defenders; and after a be- and the limited numbers engaged in them, do not leaguerment of twenty-three months, the place call for special mention. Of the pseudo-crusades, surrendered. But the crusaders were not united three deserve notice for the important results that among themselves. Philippe soon after returned to followed from them. Firstly, in 1209, there was France; and Richard, after accomplishing prodigies that against the Albigenses (q.v.). Secondly, on of valour, which excited the admiration of the the principle that it was binding on the servants Saracens, concluded a treaty with Saladin, by which of the church to do battle with all outside its pale, *the people of the West were to be at liberty to in 1230 the Teutonic knights were called on by make pilgrimages to Jerusalem, exempt from the Gregory IX. to undertake a crusade against the taxes which the Saracen princes had in former heathen Prussians on the shores of the Baltic. times imposed.' This, as has been previously The result was the complete subjugation of the noticed, was all that had been claimed by the first Prussians, and the establishment in their country crusaders. On the 25th of October 1192, Richard of the Teutonic military order till its extinction at set sail for Europe.

the battle of Tannenberg in 1410. Thirdly, in 1262 Fourth Cruscule.-Crusading unfortunately now Urban IV., jealous of the growing power of Man. became a constituent of the papal policy; and in fred, king of Sicily, son of the Emperor Frederick 1203 a fourth expedition was determined upon by II., offered Manfred's crown to Charles of Anjou, Pope Innocent III., although the condition of the brother of St Louis of France, and gave to this disChristians was by no means such as to call for it. possession the name of a crusade. A protracted It assembled at Venice; but how entirely secular war ensued, which resulted in the House of Anjou crusading had become, will be seen from the fact gaining the kingdom of Naples, and the House of that the army never went to Palestine at all, but Aragon the kingdom of Sicily. The terrible wars preferred to take possession of the Byzantine of the 16th century between France and Spain for empire. The leader of this host of pseudo.crusaders, supremacy in Italy were the direct consequence of Baldwin, Count of Flanders, was seated on the this pseudo-crusade. throne of the East in 1204, and thus founded the Effects of the Crusades.- While we cannot help Latin empire of Constantinople, which lasted for deploring the enormous expenditure of human life fifty-six years. Nothing was achieved in this which the crusades occasioned, it is impossible to crusade for the recovery of Jerusalem, but Inno- overlook the fact that they indirectly exercised a cent had his reward in the temporary supremacy most beneficial influence on modern society. They of the papal see over the Eastern Church.

secured for humanity certain advantages which it Fifth Crusade.- This was commanded by Frede. is difficult to see could have been otherwise rick II., emperor of Germany. It began in 1228, obtained. Guizot, in his Lectures on European and terminated in a treaty between that monarch Civilisation, endeavoured to show their design and and the sultan of Egypt, by which Jerusalem (with | function in the destinies of Christendom. To the CRUSCA

CRUSTACEA

595

first chroniclers,' he says, “and consequently to the limbs, are very generally distinguishable. The first crusaders, of whom they are but the expres. segmentation is never developed in the Ostracod sion, Mohammedans are objects only of hatred : it, water-fleas, and is often lost in degenerate forms. is evident that those who speak of them do not | By the development of shields (Apus), bivalve know them. The historians of the later crusades shells (water-fleas), and mantles (Cirripedes), the speak quite differently: it is clear that they look | real form is often obscured. As to appendages, the upon them no longer as monsters ; that they have head usually bears two pairs of 'antennæ, a pair of to a certain extent entered into their ideas; that mandibles, and two pairs of maxillæ; the thorax is they have lived with them; and that relations, always limb-bearing except in utter degeneracy; and even a sort of sympathy, have been established and the abdomen of the majority also carries between them.' Thus the minds of both, but par. appendages. The typical form of limb, on which ticularly of the crusaders, were partly delivered so many changes are rung, consists of a basal piece from those prejudices which are the offspring of and two more or less jointed forks. The cuticle ignorance. A step was taken towards the entran. | varies greatly in degree of firmness, but is always chisement of the human mind.' Secondly, the chitinous (see Chitin) and often much calcified. crusaders were brought into contact with two Glands open on various parts of the surface, and civilisations, richer and more advanced than their may be of use for preliminary digestion, for egg. own-the Greek and the Saracenic; and it is attachment, for mooring the animal, &c. The beyond all question that they were mightily struck colouring of the body is often very brilliant and with the wealth and comparative refinement of beautiful (see PIGMENTS). It is sometimes like that the East. Thirdly, the close relationship between of the surroundings, and is occasionally associated the chief laymen of the West and the church, with sexuality. The power of colour-change is also occasioned by the crusades, enabled the former to not uncommon. Sapphirina is said to rival the inspect more narrowly the policy and motives of humming-bird in its splendour. While the nervous the papal court. The result was very disastrous system in general retains the Arthropod characto that spirit of veneration and belief on which the teristics, the ventral ganglia are often concentrated church lives, and in many cases an extraordinary (as in crabs). The majority possess compound freedom of judgment and hardihood of opinion eyes, which in one large division are stalked. were induced—such as Europe had never before Eyes are absent in some subterranean forms, and dreamed of. The immediate results of the are lost during the development of Cirripedia (q.v.) crusades, however, went altogether to strengthen and many parasites. In the Euphausida there are the power of the church. Through their means very numerous eye-like structures or luminous the popes found an easy method of ridding them organs over the body. Smelling hairs usually occur selves of refractory monarchs; and by the exor on the first antennæ, and auditory hairs have been bitant taxes levied in the name of the cross they | frequently observed, usually more or less inclosed practically rendered all the kingdoms of the West | in sacs. The alimentary system, which consists of their tributaries. Fourthly, great social changes fore, mid, and hind gut, is usually simple, except as were brought about. A commerce between the regards the hard masticating parts often developed East and West sprang up, and towns—the early on the cuticle of the anterior portion. In some para. homes of liberty in Europe-began to grow great sitic forms the entire system degenerates. "The and powerful. The crusades, indeed, 'gave mari | body-cavity is usually a good deal filled up by the time commerce the strongest impulse it had ever muscles and viscera; it contains the blood-fluid, received.'

which is occasionally faintly coloured with hæmoSee Gibbon's History of the Decline and Fall of the globin, tetronerythrin, and other pigments, and Roman Empire; Milman's Latin Christianity; Hal. includes amboid elements. A heart is usually lam's History of the Middle Ages ; Mill's History of the present in the thoracic region, and is often in. Crusades ; Cox's History of the Crusades ; Heeren's Essay closed in a special part of the body-cavity-the on the Influence of the Crusades; the great Recueil des

pericardium. In higher forms the blood passes Historiens des Croisades, issued by the Académie des In

by distinct arteries to the bodies, is gathered up in scriptions; and Archer and Kingsford, The Crusades (Nations Series,' 1894); and the articles BALDWIN,

venous spaces and sinuses, is purified in the gills, GODFREY, JERUSALEM, RICHARD I., SALADIN, WILLIAM

and returns to the pericardial sac and heart. OF TYRE, &c.

The respiratory system is typically represented Crusca, ACCADEMIA DELLA. See ACADEMY,

by distinct gills variously attached ; in many cases DELLA CRUSCAN SCHOOL.

water flows in and out at the anus, and probably

effects an anal respiration; in many lower forms Crusenstolpe, MAGNUS JAKOB, Swedish the blood is simply purified by being exposed under political writer, was born at Jönköping, 11th the skin. The excretory system is never very March 1795. He wrote novels, elaborate historical marked. The green glands of higher forms, the works, pamphlets, and contributed to the news. shell-glands of Phyllopods and Copepods, and papers. His Stillningar och Förhollenden, oarried certain other structures, are excretory. The repro. on from 1838 till 1865, applied vigorous and unspar. ductive system presents many variations. The ing criticism to the questions and persons of the sexes are usually separate, but most Cirripedes are day. His bitter opposition to government cost him hermaphrodite. In the Cymothoida (Isopoda) three years' imprisonment (1838–41). He died 18th the sexual organ of the young animal is male-of January 1865.

the old, female-in function. The glands are Crustacea, a large and important class of usually thoracic, and the ducts double. Some of Arthropod animals, including crabs, lobsters, the appendages are often modified for copulation or shrimps, sand-hoppers, wood-lice, water-fleas, bar. | egg-retaining. The spermatozoa are peculiar in nacles, acorn-shells, &c. The class contains such being usually non-motile. The eggs are in most variety of structure that general characters are cases carried about by the female, but are occa. hard to find. They are almost all aquatic, but a sionally laid on water plants, &c., or in the water. few (e.g. wood-lice and land-crabs) are terrestrial. According to Bates, Podocerus capillatus builds a The majority are marine, but great numbers in nest of interlaced seaweed. Parthenogenesis (q.v.) habit fresh water. The form of the body is very has been observed in some of the lower forins. variable, as may be seen by contrasting crab and Complemental' males occur among the hermaph. barnacle. A head with five pairs of appendages, a rodite Barnacles and Acorn-shells (q.v.). limb-bearing thorax more or less united to the Life-history. The development of Crustaceans former, and a segmented abdomen with or without is usually indirect—that is to say, the newly.

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hatched young is unlike, often very unlike, its start at the Zoæa point; lobsters abbreviate still parent. Even when there is no metamorphosis further, and begin as Mysis forms; the crayfish has after hatching, traces of transformation, as opposed found the shortest cut of all. Some of the lower to continuous development, are sometimes to be Crustaceans never get far past the Nauplius stage, detected in the earlier history while the embryo while others remain practically on the Zoæa grade. is still within the egg-case. (a) The crayfish The life-histories of "Crustaceans vividly illustrate (Astacus) has a very much abbreviated life-history, how the individual life-history is a rehearsal of the for the newly-hatched form is almost quite like historic evolution of the kind, or more technically, the adult. (b) The newly-hatched lobster (Hom. | how ontogeny recapitulates phytogeny. arus ), however, begins life a little further back, Habit of Life. The acorn-shells fastened to the in what is known as the Mysis stage, in which rocks, wafting in their food by their curled feet ; the thorax bears two-branched swimming append the barnacles moored to floating logs and shipages. (c) Most other higher Crustaceans (e.g. bottoms ; such extremes of parasitism as are illuscrabs ) begin at a still lower level, in what is called trated by Sacculina on hermit crabs; the hermitthe Zova stage, with a short unjointed thorax and crabs themselves, stealing the shells of Gasteropods, a segmented abdomen without limbs. (d) The or entering into partnership with sea-anemones;

the thousand minute and active water-fleas; the wood-lice, quite terrestrial; the brine-shrimps in the salt-pools; the fresh-water crayfish ; the giant marine lobsters ; the land-crabs, hàbituated to inland life, sufficiently suggest how varied are the habits of Crustaceans. Some Crustaceans form masking shelters for themselves out of Tunicates, or get covered over by a concealing growth of seaweed, sponge, hydroids, &c. A few forins are known to make a stridulating noise. The general intelligence of the class is probably considerable (see CRAB). On the whole the members of this class are active animals, but on each side of the medium activity of the majority there are extremes. Thus, not a few active marine forms are phosphorescent, while parasitism (to the extent of some 700 species ) occurs in most of the subdivisions. Many of the parasites are very striking in the contrast between the free-swimming young and the ne plus ultra of degeneracy in the adults (see DEGENERATION, PARASITISM). Some of the interesting cases of Commensalism (q.v.) have been referred to under that title; while some

of the external parasites show in the castration, Development of a Prawn (Penæus):

&c. which they effect on their hosts, how real in a, Nauplius; 6, Zoxa; c, Mysis; d, adult.

such cases is the direct influence of the animate

Environment (q.v.). The diet of Crustaceans is Decapod Penæus, a shrimp-like creature, has its very varied; the majority are carnivorous and life-history still more drawn out. It quits the egg aggressive; many feed on dead creatures and as a Nauplius, an unsegmented larva with three organic debris in the water; others depend largely pairs of appendages, the first unforked, the other upon plants. They often lose limbs in fighting or two pairs double-branched. These correspond to otherwise, and have the power of replacing what the first three appendages of the adult. The median they have lost. eye is also a distinctive feature in the Nauplius Classification (after Claus).-(A) Entomostraca. larva. The Penæus Nauplius has with successive Lower forms, small, simple, with variable number moults first to become a Zoæa, and then a Mysis, of rings and appendages, with not more than three and then an adult. It is as a Nauplius that the appendages concerned in mastication, usually lear. majority of lower Crustaceans leave the egg, but ing the egg as a nauplius. (1) Phyllopoda : (a) then they do not climb so high. To understand | Branchiopoda-e.g. Biine-shrimps (q.v.), Apus, the circuitous life-history of a form like Penæus, Estheria, &c. ; (b) Cladocera—the common 'waterwe have to note that it begins in the Nauplius flea' Daphnia, Moina, &c. (2) Ostracoda-comstage, at the level of the lowest Crustaceans, and mon Cypris (q.v.), Cypridina. (3) Copepodagradually climbs through a series of higher and common Cyclops (q.v.), Lernæa, &c. (4) Cirri. higher stages, each of which is represented per. pedia-Acorn-shells, Barnacles (q.v.), Sacculina, manently by some division of Crustaceans which &c.—(B) Malacostraca. Higher, larger forms, have not risen higher. If the various grades from | with nineteen segments, with more than three Nauplius up to Decapod adult represent successive appendages concerned in mastication, usually historic levels, now exemplified in the classification quitting the egg at a higher level than the Nau. of Crustaceans by those which were left behind at plius : (1) Leptostraca, Nebalia, a primitive form each lift, what the Penæus does is to recapitulate with bivalve shell; (2) Arthrostraca, with free in its individual life-history the historic evolution thorax, and no cephalothoracic shield, eyes sesof the class. This idea has been beautifully applied sile: (a) Amphipoda-Sand-hoppers (9.v.), Capto Crustaceans in Fritz Müller's Facts for Darwin. rella, &c. ; (6) Isopoda—Wood-lice (9.v.), Asellus, The various grades of Nauplius, Zoæa, Mysis, and Tanais, &c. (3) Thoracostraca, with all or part of adult Penæus (overlooking intermediate ones) thorax fused to head, and with a cephalothoracic may be compared to stations which mark the shield, eyes mostly stalked : (a) Cumacea, sessile. gradual extension of the Crustacean line of advance. eyed—Cuma ; (6) Stomatopoda, with gills on abPenæus has to travel along the rails laid down by dominal feet-Squilla ; (c) Podophthalmata, with the ancestral history, and has to stop for variable stalked eyes and large shield: (i) Schizopoda, periods at the successive stations between the with eight pairs of double thoracic feet-Mysis; starting point and the terminus. Crabs skip over (ii) Decapoda, with thorax fused to head, and the Nauplius station, and like most other Decapods last five thoracic feet not double; long-tailed

CRYPTOGRAPHY

CRYSTALLOGRAPHY

599

in British history, cryptography has at no time disguise of music, the notes, rests, expression. been in greater requisition than during the Civil marks, &c., standing for letters. War. Charles I.'s celebrated letter to the Earl of All the methods, however, of cryptography may Glamorgan (afterwards Marquis of Worcester), in thus be summarised : (1) By invisible ink; (2) which he made some compromising concessions to the by superfluous words ; (3) by misplaced words; Catholics of Ireland, was composed in an alphabet (4) by vertical and diagonal reading ; (5) hy arti. (sometimes supposed to be Charles's own, but more ficial word-grouping ; (6) by stencil-plates cut out probably Worcester's invention) of twenty-four so as to show certain words beneath; (7) by using short strokes variously situated upon a line (see two letters (Lord Bacon's cipher); (8) by trans. OGAM). Other letters by the same monarch are posing the letters ; (9) by substitution of letters ; to appearance a mere series of numbers of two or (10) by counterpart tabulations ; (11) by mixed three figures divided by semicolons. In such cases symbols ; (12) by a printed key and code-book, it was necessary that the two parties engaging in used chiefly in telegrams; (13) by the employment the correspondence should have previously con- of numerals. certed what words each number was to represent. The present century has seen the decline of

In the reign of William III. the Jacobites in- cryptography for all practical purposes, and the art vented many curious ciphers to enable them to is now only regarded as a curious study, closely communicate with their exiled king. All the connected with the history of all nations. Jacobite clubs had distinct methods of their own Cryptomeria, or JAPANESE CEDAR. This their great aim being to write in such a manner lofty and beautiful hardy coniferous tree (C. that the very ciphers themselves should pass

hemselves should . pass japonica) is widely distributed in mountain dis. through their enemies' hands without suspicion, i tricts of Japan and China, as well as cultivated This they accomplished by means of sympathetic in many varieties. It was introduced by Robert inks. A favourite Jacobite cipher was the use of Fortune in 1842, and has since passed into cultiva. parables, conveying, by means of ordinary lan

tion. Although originally confused with the guage, a double meaning, which only the person

cypresses, it is nearly allied to Sequoia and Taxo. acquainted with the writer's views would think of. dium. See CONIFERÆ. The use of cryptography for purposes of state in England ended, it may be said, with the Peace of

Cryptoprocta, a fierce carnivorous animal of 1815. During the Peninsular war the government

Madagascar, forming a genus and species by itself. attached a cryptographer to the office of the Minister

Semi-plantigrade, and with beautiful fur, it refor Foreign Affairs to read and write the ciphers

sembles a large polecat, three feet long, and received and despatched. It is said that on more

attacks the largest animals with great ferocity. than one occasion the minister was unable to com.

Crystalline Rocks, a name given to all rocks prehend his own cipher.

having a crystalline structure. The crystalline The earliest elaborate treatise on writing in

texture may either be original or superinduced. cipher is the Steganographia (Frankf. 1606) of the

Thus some crystalline rocks, such as certain cal. abbot John Trithemius, à MS. copy of which was

careous masses, owe their origin to chemical prebought for a thousand crowns at Antwerp by Dr Dee 'cipitation from water, while others again, such as in 1563. Lord Bacon. who esteemed cruntocranhv lavas, have consolidated from a state of igneous one of the most useful arts of his time, framed

fusion. There is another large class of crystalline what he believed a not easily penetrable cipher

rocks, the crystalline granules of which present in which he employed only a and b, arranging each

a remarkable foliated character-that is, they are of these letters in groups of five, in such collocations

arranged in more or less parallel layers (see as to represent all the twenty-four letters. Thus

SCHISTS). This peculiar schistose structure appears aabab, ababa, babba conveyed the word fly. In

to have been superinduced-the original rocks his De Augmentis he styled this an omnia per omnia

having been either fragmental or crystalline or cipher, believing that in this case preconcertment

both-and the result of great heat and pressure. would be necessary; but in reality any clever

Such highly altered rocks occur in the neighbour. modern decipherer could have read any letter com

hood of masses of granite, and cover wide regions, posed in such a manner if it were of any length.

where there is abundant evidence to show that the Mr Donnelly, in his work The Great Cryptogram,

strata have been subjected to enormous compres. endeavours to prove that Bacon inserted a cipher

sion, crushing, and crumpling-having been folded in the Shakespearian plays - which he claims is j and fractured and pushed violently over each other the work of the great philosopher-but the cipher

for distances of sometimes 15 miles and more. It is of so elaborate a kind tliat nobody but Mr

is therefore believed that pressure and the heat Donnelly has been able to follow its intricacies.

engendered by great earth-movements, and the in. The unfortunate Earl of Argyll used a mode of trusion of plutonic igneous matter, are among the secret writing which consisted in setting down the most potent agencies in the production of schistose words at certain intervals, which he afterwari's

structure. filled op with other words, making of the whole Crystallites, minute non-polarising bodies (the something intelligible, but of no use to any one | result of incipient crystallisation ) occurring in the else reading the message. The Marquis of Wor. vitreous portions of igneous rocks. See IGNEOU'S cester invented a cipher composed of dots and lines ROCKS. variously ordered within a geometrical figure ; while Crystallography (from the Greek krustallos, Dr Blair made one of three dots, placed over, under,

ice,' an idea among the ancients being that or on the line, by which he could represent no rock-crystal, which may be taken as a type of fewer than eighty-one letters, figures, or words. | crystalline minerals, resulted from the subjection The Doctor, in his able article in Rees's Cyclopedin, l of water to intense cold ). Miner declares this cipher to be as nearly as possible organic bodies generally (exa!

organic bodies venerally (examples, rock-crystal. undecipherable by strangers ; but two years after

o years after- | fluor-spar, alum, and sugar) exist in the crystalline waris Mr Gave, of Norwich. published a pamphlet state . and when we examine all

whether on purpose to solve Dr Blair's riddle." As he occurring naturally or obtain

or obtained artificially, certain devoted fourteen closely printed octavo pages to laws have been discovered, and

vered and phenomena observed. the explanation, any description of the cipher is and these laws and phenom

d phenomena constitute the beyond the limits of this article. Mr Thicknesse, science of crystallography, a well-known expert of the 18th century, also more important laws and pri

and principles of the science devised a plan of conveying information in thel (1) Law of Constancy o

of Angles.-Crystals of the

ngo

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hatched young is unlike, often very unlike, its start at the Zoæa point; lobsters abbreviate still parent. Even when there is no metamorphosis further, and begin as Mysis forms; the crayfish has after hatching, traces of transformation, as opposed found the shortest cut of all. Some of the lower to continuous development, are sometimes to be Crustaceans never get far past the Nauplius stage, detected in the earlier history while the embryo while others remain practically on the Zoæa grade. is still within the egg-case. (a) The crayfish The life-histories of "Crustaceans vividly illustrate (Astacus) has a very much abbreviated life-history, how the individual life-history is a rehearsal of the for the newly-hatched form is almost quite like historic evolution of the kind, or more technically, the adult. (b) The newly-hatched lobster (Hom. how ontogeny recapitulates phytogeny. arus ), however, begins life a little further back, Habit of Life.-The acorn-shells fastened to the in what is known as the Mysis stage, in which rocks, wafting in their food by their curled feet ; the thorax bears two-branched swimming append. the barnacles moored to floating logs and shipages. (c) Most other higher Crustaceans (e.g. bottoms ; such extremes of parasitism as are illuscrabs ) begin at a still lower level, in what is called trated by Sacculina on hermit crabs; the hermitthe Zoca stage, with a short unjointed thorax and crabs themselves, stealing the shells of Gasteropods, a segmented abdomen without limbs. (d) The or entering into partnership with sea-anemones;

the thousand minute and active water-fleas; the wood-lice, quite terrestrial; the brine-shrimps in the salt-pools; the fresh-water crayfish; the giant marine lobsters; the land-crabs, habituated to inland life, sufficiently suggest how varied are the habits of Crustaceans. Some Crustaceans form masking shelters for themselves out of Tunicates, or get covered over by a concealing growth of seaweed, sponge, hydroids, &c. A few forms are known to make a stridulating noise. The general intelligence of the class is probably considerable (see CRAB). On the whole the members of this class are active animals, but on each side of the medium activity of the majority there are extremes. Thus, not a few active marine forms are phosphorescent, while parasitism (to the extent of some 700 species) occurs in most of the subdivisions. Many of the parasites are very striking in the contrast between the free-swimming young and the ne plus ultra of degeneracy in the adults (see DEGENERATION, PARASITISM). Some of the interesting cases of Commensalism (9.v.) have been referred to under that title; while some

of the external parasites show in the castration, Development of a Prawn (Penæus):

&c. which they effect on their hosts, how real in a, Nauplius ; 6, Zoæa; c, Mysis; d, adult.

such cases is the direct influence of the animate

Environment (9.v.). The diet of Crustaceans is Decapod Penæus, a shrimp-like creature, has its very varied; the majority are carnivorous and life-history still more drawn out. It quits the egg aggressive; many feed on dead creatures and as a Nauplius, an unsegmented larva with three organic debris in the water; others depend largely pairs of appendages, the first unforked, the other upon plants. They often lose limbs in fighting or two pairs double-branched. These correspond to otherwise, and have the power of replacing what the first three appendages of the adult. The median they have lost. eye is also a distinctive feature in the Nauplius Classification (after Claus).-(A) Entomostraca. larva. The Penæus Nauplius has with successive Lower forms, small, simple, with variable number moults first to become a Zoæa, and then a Mysis, of rings and appendages, with not more than three and then an adult. It is as a Nauplius that the appendages concerned in mastication, usually leav. majority of lower Crustaceans leave the egg, but ing the egg as a nauplius. (1) Phyllopoda : (a) then they do not climb so high. To understand Branchiopoda-e.g. Brine-shrimps (q.v.), Apus, the circuitous life-history of a form like Penæus, Estheria, &c.; (6) Cladocera—the common water. we have to note that it begins in the Nauplius Alea' Daphnia, Moina, &c. (2) Ostracoda-comstage, at the level of the lowest Crustaceans, and mon Cypris (q.v.), Cypridina. (3) Copepodsgradually climbs through a series of higher and common Cyclops (q.v.), Lernæa, &c. (4) Cirrihigher stages, each of which is represented per. pedia-Acorn-shells, Barnacles (q.v.), Sacculina, manently by some division of Crustaceans which &c.—(B) Malacostraca. Higher, larger forms, have not risen higher. If the various grades from with nineteen segments, with more than three Nauplius up to Decapod adult represent successive appendages concerned in mastication, usually historic levels, now exemplified in the classification quitting the egg at a higher level than the Nauof Crustaceans by those which were left behind at plius : (1) Leptostraca, Nebalia, a primitive form each lift, what the Penæus does is to recapitulate with bivalve shell; (2) Arthrostraca, with free in its individual life-history the historic evolution thorax, and no cephalothoracic shield, eyes sesof the class. This idea has been beautifully applied sile: (a) Amphipoda-Sand-hoppers (q.v.), Capto Crustaceans in Fritz Müller's Facts for Darwin. rella, &c.; (b) Isopoda—Wood-lice (q.v.), Asellus, The various grades of Nauplius, Zoæa, Mysis, and Tanais, &c. (3) Thoracostraca, with all or part of adult Peneus (overlooking intermediate ones) | thorax fused to head, and with a cephalothoracic may be compared to stations which mark the shield, eyes mostly stalked : (a) Cumacea, sessilegradual extension of the Crustacean line of advance. eyed-Cuma; (6) Stomatopoda, with gills on abPenæus has to travel along the rails laid down by dominal feet-Squilla ; (c) Podophthalmata, with the ancestral history, and has to stop for variable stalked eyes and large shield: (i) Schizopoda, periods at the successive stations between the with eight pairs of double thoracic feet-Mysis; starting point and the terminus. Crabs skip over (ii) Decapoda, with thorax fused to head, and the Nauplius station, and like most other Decapods last five thoracic feet not double ; long-tailed

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