CRUSTACEANS, ETC.-1. Grass-mite.

2. Porcupine tick. 3. Cheese-mite. 4. Itch-mite. 5. B 11. Wool-crab. 12. Purse-crab. 13. White-bait. 14. Galathea. 15. Spiny-lobster. 16. 22. Fish-millepede. 23. Wood-louse. 24. Pill-millepede. 25. Fish-louse. 26. Shrimp30. Water-flea. 31. Cypris. 32. Crab-flea.

Cryophorus.

longed so as to oppose the last joint, which becomes attached as to the side of it; and these are used for seizing and tearing food. The limbs of the first thoracic rings are, in many C., organs still more intimately connected with the mouth, and have received the name of foot-jaws, the transition from the true mandibles and maxillæ to the organs of locomotion being often very gradual.. The mouth of some small parasitic C. is, however, formed for sucking, and not for tearing and masticating food. The digestive organs are very simple in all; there is a short but capacious gullet, a large stomach, and a straight and simply intestinal tube. The pyloric region of the stomach, however, is furnished with a remarkable apparatus of hard tubercles or sharp teeth for grinding or tearing food, supplementary to the external organs of the mouth. Almost all of the C. feed on animal food, and they are very voracious. A few feed on vegetable food. The nervous system of C. agrees generally with that of insects, and exhibits many gradations of division and concentration. C. in general, appear to possess all the five senses. Their eyes are either simple (stemmatic), aggregate (consisting of several stemmata under a common cornea), or compound. The compound eyes are often on foot-stalks. The gills are variously placed; in the internal cavity, under the carapace-the enlargement of the plate of a single ring, which covers the thoracic rings in crabs, etc.; on the thoracic limbs; on the abdominal or false legs, etc. The heart is always in the middle line of the body, is of various form, and distributes the blood by a number of trunks through the system; but the blood returns to venous sinuses, from which, and not from the heart, it is sent into the gills, and it is not until after its aëration in the gills that it comes to the heart again; not, however, without being mixed with venous blood which has not undergone the same aëration. The sexes are distinct in most of the C.; and they are all oviparous. A sort of incubation of the eggs takes place, in order to which they are carried under the abdomen or under the thorax of the female, attached to the false legs or to some of the thoracic appendages. It has recently been discovered, contrary to former belief, that C.-or at least many of them-undergo metamorphoses; and the curious creatures known by the name zoea have been found to be the young of crabs.

The greater number of C. are marine: some inhabit fresh waters, running or stagnant; comparatively few are terrestrial.

Cuvier divided Č. into two sections, malacostraca and entomostraca; the former section containing the orders decapoda, stomapoda, læmodipoda, amphipoda, and isopoda; the latter the branchiopoda and pacilopoda. Another division has been more recently proposed by Milne Edwards, and very generally adopted into xyphosura (the genus limulus alone), having a mouth destitute of jaws, and for which legs perform the office of jaws; marillosa, or masticating C.; and edentata, or suctorial crustaceans.

CRUST OF THE EARTH. It having once been believed by geologists that the interior of our globe is in a state of fusion from heat, they have given the name of crust of the earth to the external solid covering. Man has been able to penetrate but a short way into the crust, and he cannot safely reason on his observations made at or near the surface, regarding the condition of the crust to a greater depth than a few miles, at the most 10-all beyond is little more than guess-work. The materials of the crust are not thrown confusedly together, but distinct mineral masses are found to occupy definite spaces, or to exhibit a certain order of arrangement. All these may be classified in reference either to their origin, which is aqueous (see AQUEOUS ROCKS) or igneous (q.v.); or to their relative age, as primary (q.v.), secondary (q.v.), and tertiary (q.v.). CRUVEILHIER, JEAN, 1791-1874; a French anatomist educated in the university of Paris, where he became professor of anatomy, on which science he published three works. He was commander of the legion of honor.

CRUVELLI, SOPHIE, Baroness Vizier, b. 1824; a German singer, having a soprano voice of great strength and purity, and in her day the most popular of vocalists. On marrying baron Vizier, in 1856, she left the stage.

CRUYS, CORNELIS, the founder of Russian maritime power, was b. June 14, 1657. He was a rear-admiral in the Dutch service when czar Peter the great, noticing his abilities, pursuaded him to go to Moscow. There he arrived Oct. 15, 1698, and was received with great splendor, and soon appointed vice-admiral. His services to Russia were of various kinds; to him it owed its first dockyards, canals, and charts, the organization of its navy, and its victories over Sweden and Turkey in 1708-1710. After a short period of disgrace, C. was received back to favor. He died in 1727, possessor of an imperial domain in Kexholm, and owner of the island Birken in Finland. It is in memory of him the white flag with the blue cross (Dutch, kruis) still floats from the Russian men-of-war.

CRY OLITE is a double fluoride of aluminium and sodium (NaF, Al,F.), and is important as a source of the metal aluminium (q.v.).

CRYOPHORUS (Gr. kryos, cold, and phero, I carry) is an instrument consisting of a glass tube with a bulb at both ends. A little water is present in one of the bulbs, and when the second bulb, containing only water-vapor, is placed in a freezing mixture, the vapor condenses, which causes more vapor to rise from the water in the first bulb. The IV.-16a.

Cryptography.

result of this vaporation from the first bulb is the abstraction of much heat, and ultimately the remaining water passes into a frozen state.

CRYPT (Gr. krypto, I hide), a vault under a church, either entirely or partly under ground. Crypts do not generally extend beyond the limits of the choir or chancel, and they are often of much smaller dimensions. Crypts were formerly used as chapels, and provided with altars and the other furniture requisite for the celebration of religious services; and they were also very frequently used as places of sepulture. It sometimes happens that a new church has been erected over the C. belonging to the old one. One of the largest crypts in England is that under Canterbury cathedral; but there are few finer specimens of the C. any where than that under Glasgow cathedral, which has been recently freed from rubbish and restored. Crypts seem to have originated in the customs of the early Christian ages. The tombs of the martyrs were first used as churches; and then churches were built above them.

CRYPTO-CALVINISTS, a name given to Melanchthon and those who agreed with him in wishing to unite the Lutherans and Calvinists, and especially in his supposed leaning towards the Calvinistic view of the Lord's Supper as shown in the difference between the original and the altered Augsburg confession. The former said: "The body and blood of Christ are truly present in the Lord's supper in the form of bread and wine, and are there distributed and received by the communicants: therefore the opposite doctrine is rejected." In the latter, the last clause is omitted. Luther did not approve the alteration, but tolerated Melanchthon's change of doctrine. Many, however, called him a Crypto-Calvinist. The truth seems to have been that he did not consider that either opinion was a sufficient bar to communion with Christ, and therefore thought that both of them ought to be allowed. The controversy was becoming violent before his death, but afterwards it broke out with great virulence, and continued with alternate success on each side for 50 years; during which time frequent attempts were made to suppress the Calvinistic opinions by imprisoning their leading advocates, and, at last, in 1611, by the execution of chancellor Nicolas Crell.

CRYPTOG'AMOUS PLANTS (Gr. kryptos, concealed, and game, marriage) are those which have no true flowers, and no known male or female organs of fructification, and whose seeds, called spores, consist only of a single cell, and contain no embryo, but germinate indifferently from any point; and which Jussieu therefore designated acotyledo nous plants (q.v.). The name C. P. was invented by Linnæus, and the cryptogamia form a class of his sexual system, very distinct from all the rest. See BOTANY. Many C.P. have no leaves; some have not even a root, and those which are lowest in organization consist only of a single cell. Many are parasitic. Many look as if dead in a dry atmosphere, and are revivified by rain. They are the lowest in organization of the vegetable kingdom, and are divided into filices (ferns), marsileacea, lycopodiacea (club-mosses), equisetacea (horse-tails), musci (mosses), hepatica, lichens, fungi, characeœ, and algæ.

CRYPTOGʻRAPHY, the art of secret writing, more commonly called the art of writing in cipher (from Arabic sifr, void), has been in use from an early date in correspondence between diplomatists and others engaged in important affairs requiring secrecy. In modern times, it has been the subject of learned care to lord Bacon, the ingenious marquis of Worcester, Dr. Wallis, bishop Wilkins, Thicknesse, Falconer, Blair, etc. In our own history, it has at no time been in greater requsition than during the civil war, and among the politicians of the 17th century. And even now, when there is happily less need for mystery among our statesmen, the need for a perfectly undecipherable mode of secret communication has again had to be looked for, in order that information may pass by the electric telegraph without being understood by the officials in connection with the apparatus.

One of the most simple methods of C. is to use, instead of each letter of the alphabet, a certain other letter at a regular interval in advance of it in that series. Such was a mode of secret writing used by Julius Cæsar. As a variety upon this plan, the alphabet is used invertedly-z for a, y for b, x for c, and so on. Or while the first seven letters

are represented by the second seven, the next six may be represented by the last six. And many other variations may be adopted. But for all modes like these, there are modes of decipherment far from difficult. It is only necessary, in general, to bear in mind certain peculiarities of the language presumed to be used. Say it is the English. We readily remember that e is the most frequent letter; that ea and ou are the double vowels which most frequently occur; that the consonants most common at the ends of words are r, s, and t; etc. We also know how a single letter must be either the pronoun I or the article a; how an, at, and on are the most common words in two letters; how the and and are the most frequent words in three letters, etc. By taking advantage of these few obvious principles, a tolerably skilled decipherer will read almost any such piece of cryptographic writing in five minutes. The Times newspaper often gives, in its advertising columns, correspondence on delicate subjects, even assignations for elopements, written in this manner, the writers of which are of course little aware how open their secrets thus become to society.

Politicians and important personages conducting affairs of difficulty became long ago sensible of the necessity of using ciphers of greater abstruseness. The celebrated letter of Charles I. to the earl of Glamorgan, in which he made some condemning con