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The great extent of the space which, for the reasons be-
fore mentioned, is unavoidably occupied by an army in the
field, renders it, in most cases, impossible to fortify the site
of the encampment by a continuous line of parapet like that
with which the Roman armies surrounded themselves on
taking up a defensive position; and the security of a modern
army against surprises is now obtained principally by the
situation being difficult of access, from streams, marshes, or
inequalities of the ground, and by keeping numerous ad-
vanced posts to watch all the approaches by which an enemy
might arrive at the camp.

whole extent in front of a regiment consisting of 13 com- | that which the British army occupied before Lisbon in 1810
panies, each of 150 men, was 712 feet. Originally, it seems, This consisted of a double line of detached redoubts con-
the officers' tents were placed in front of those occupied by structed on all the commanding points of ground, for the
the men; but Sir James Turner states that Henry of Nas- purpose of defending the four great roads and the accessible
sau changed that custom, and caused them to be placed in passes by which the enemy could approach to that city.
the rear, as they are at present, in order that the soldiers The first line began at the mouth of the Zizandra on the
might be enabled to have more easy access to the parade in Atlantic; it crowned the heights above Torres Vedras, and
front of the line. (Grose, ii., pp. 213, 214.)
following the chain of Monte Graça, extended to the Tagus
at Alhandra, its whole length being about 29 miles. The
second was about six miles in rear of the first; it began at
the mouth of the S. Lorenzo, on the ocean, passed over
the heights at Mafra, Montechique, and Bucellas, and
reached the Tagus at Quintella, its whole extent, in length,
being about 24 miles. The weakest part seems to have
been the valley of Calhandria, near the Tagus, on the ex-
terior line; but this part was afterwards strengthened by a
double row of abatis, besides breast-works of earth and thick
stone walls. When the lines were completed, they consisted of
152 redoubts, armed, in all, with 534 pieces of ordnance, and
required above 34,000 men for their garrisons. The dis-
bursements for their construction amounted to nearly
100,0002. (Colonel Jones, Memoranda on the Lines about
Lisbon, p. 107.) [LINES OF INTRENCHMENT, MILITARY
PoSITIONS.]

There are, however, some circumstances which render it
indispensable that an encampment should be strengthened by
fortifications; as when the troops are inexperienced or the
army is deficient in cavalry; but chiefly when a position is
occupied which it is of the utmost importance to hold, be-
cause the possession of it would be advantageous to the
enemy. The latter may then be reduced to the alternative
of attacking the encampment at a disadvantage, or of suffer-
ing a loss of valuable time in making the movements neces-
sary to turn it. In these cases, every resource of the engi-
neer in the construction of works and in obstructing the ap-
proaches should be put in practice for the purpose of aug-
menting the resistance which the army may be capable of
making.

A continuous line of works may therefore be admissible for an army inferior to that of the enemy, provided the extent of the line be not so great as to prevent the intrenchments from being sufficiently manned in every part; but a camp so fortified would possess no advantages for an army which is strong enough to assume the offensive on a favourable occasion presenting itself; and it is evident that, in this case, it would be sufficient to construct merely a few redoubts in situations from whence a fire of artillery might be directed for the purpose of defending the approaches, while the disposable force of the army might be kept in masses ready, at a proper time, to make a movement to the front through the intervals between the works.

ENCAUSTIC PAINTING (¿ykavorɩký, encaústike) is a kind of painting in which by heating or burning in (as the Greek term implies), the colours were rendered permanent in all their original splendour. It was not however enamelling, as some have imagined, but a mode of painting with heated or burnt wax, which was practised by the antients, various specimens of which have been preserved in the East, and which, according to some historical statements, was in use at Venice even to the time of Titian. Pliny, in his 'Natural History' (xxxv. 11), gives a short account of the invention and nature of this art. He says, 'Ceris pingere ac picturam inurere, quis primus excogitaverit non constat.' But though he expressly says wax, some persons have imagined that by ceris he here means some composition different from wax, and capable of bearing the fire, and that inurere means to enamel. In the same chapter he says that there were antiently two modes of encaustic painting, cera et in ebore, cestro, i.e., viriculo. Hoc tertium accessit, resolutis igni ceris, penicillo utendi.' The Marchese Haus, in accordance with Pliny, assumes three kinds of encaustic painting, distinguishing as an essential point, whether the cestrum (a style, or a graving tool) This principle does not, till lately, appear to have been or the pencil was employed in the execution. In the first well understood; and the cautious spirit with which a cam-mode, the wax was melted, mixed with as much earth paign was conducted during the eighteenth century con- colour finely powdered, as it could imbibe, and then this trasts strongly with the bold measures generally pursued mass spread on wood, or on a wall with a hot spatula. When in the late war. Marshal Daun, though always superior in it became cold, it was the ground, in which the designer number to the Prussians, intrenched himself with the cut the lines with a cold pointed tool (style, cestrum), and utmost anxiety; and in 1759, when he took up a position thus, properly speaking, it was not the painting but the near Dresden, though the king of Prussia had lost the wax ground that was burnt in, and the name encaustic was battle of Kunersdorf, and the Austrian army was encamped improperly given to the painting. With regard to the upon steep rocks, covered by a stream difficult to pass, yet second kind, encaustic painting on ivory, the most erronethe marshal surrounded himself with works so numerous, ous notions were long entertained. Professor Grund, of that even the smallest paths were protected by them, and Florence, who has devoted much attention to encaustic so strong, that twenty years afterwards they were in ex- painting, seems to be nearest to the truth. When the istence. But one of the most celebrated of these intrenched practice of drawing on hard wax had been brought to some camps was that which, in 1761, the king of Prussia took up degree of perfection, they proceeded to apply it on a small at Buntzelwitz in order to cover Breslau. This camp was scale to ivory, which was at that time in the highest estiformed within a chain of hills protected on three sides by mation. Ivory tablets were therefore covered with red or streams: six salient points on the contour were fortified by black wax, and the design cut in it with the style, the bastions, the fires from which would have flanked the in- object being to use the clear and smooth surface of the termediate parts of the line, and these were further pro- ivory for the lines, that they might look the more beautected by fleches constituting a sort of broken curtain tiful. This therefore was nothing more than applying to between every two redoubts. Nearly 180 pieces of artillery ivory what had previously been done on wood, or walls. were planted to defend the avenues, and the camp was The third kind is the applying the colours with the pencil. surrounded by abatis and other obstacles by which the With respect to the manner in which this was executed, approach of an enemy might be impeded. (Jomini, Traité opinions differ. The most correct notion seems to be that des Grandes Operations Militaires, tom. iv.) Such in the wax was dissolved, the colours mixed with it, and laid trenchments however avail nothing when the army is on with the pencil, and the painting then finished by careful not commanded by a man of great military genius. approximation to the fire, whence this kind of painting The French camp at Malpaquet, in 1709, is stated to became properly encaustic. For this purpose a hot iron have been fortified with a triple line, consisting of breast- (cauterium) was used. When painting had been greatly works, hedges, and felled trees; it was forced however, improved by the invention of the pencil, a new method of though with great loss, by the allies under the duke of encaustic was attempted. Encaustic wax painting had Marlborough. hitherto been designing on a coloured ground; it now became painting with wax colours burnt in. When the artist had laid on the wax ground, and traced the outlines with the style, he proceeded to the colouring. From the wax mixed with the colours he separated with the hot style

It is remarkable that, during the war in Spain, which in general was distinguished by inattention to the means of strengthening the positions occupied by the troops, one of the finest examples of an intrenched camp was afforded in

as much as he wanted to cover a certain space, and spread it over the ground, put a second, third, &c., colour next the first, so that he had local tint, half tint, and shade together, which he softened into each other with the hot style. After the whole art of encaustic painting had long been lost, the memory of it was recovered by Count Caylus, in France, who announced to the Academy of Painting the method of painting in wax in 1752: a Mr. Bachelier however had actually painted a picture in wax in 1749, and is the author of a treatise on the art and secret of wax painting; and he was the first who communicated to the public the method of performing the operation of inustion, which chiefly characterizes encaustic painting. The count kept his method secret for a time, and in 1754 exhibited at the Louvre a head of Minerva painted in the manner of the antients. This was much admired, and it was affirmed that in wax painting the colours were more permanent, purer, and brighter than in oil painting. Several other persons have made essays in this art, as Bien, Bertscher, Bar. Taube in Mannheim, W. Kalan, painter in Berlin, and Reifenstein. As neither Pliny, nor Vitruvius, nor any other antient author, has left a clear account of the methods employed, it may be reasonably doubted whether any one among the various processes employed or recommended by the moderns is the same as those of the Greeks. J. G. Walter, in Berlin, and Professor J. Roux, in Heidelberg, have recently turned their attention to wax painting; the latter is said to have left many very successfully executed wax paintings; but he did not publish his secret, though he strongly recommended it to painters in his treatise on colours (Die Farben, Heidelberg, 1828). Since 1826 Mr. Peter Kraft, at Vienna, has painted several paintings on walls, in which however only the warmed ground was covered with wax, and the colours mixed with oil of turpentine laid on it. The process made known by Montabert in his 'Traité de la Peinture,' vols. vii. and viii., has a greater resemblance to encaustic painting, properly so called. The laying on is nearly in the manner last mentioned, but a wax varnish is spread over the colours, and melted in by means of a kind of brasier. A series of paintings has been executed, according to his direction, on the walls of the royal palace at Munich, since 1831; but even here all the difficulties with respect to the durability of the ground and the colours have not been overcome.

ENCKE'S COMET, one of the periodic comets which have been ascertained to belong to the solar system, revolving round the sun in about 1200 days, within the orbit of Jupiter.

A full account of this body is contained in a memoir by Encke, published in numbers 210 and 211 of the Astronomische Nachrichten, and translated by Mr. Airy, under the title 'Encke's Dissertation,' &c., Cambridge, 1832. See also the Reports of the British Association,' vol. i. (1831-1832), and the tract of M. Arago Des Comètes en général,' in the ‘Annuaire' of 1832.

This comet is now known to have been seen in 1786 by Méchain and Messier, in 1795 by Miss Herschel, and in 1805 by M. Pons of Marseilles, and others. But the train of investigation which established it as a periodic comet (all the preceding observations having been supposed to be of different bodies) dates from the observations of M. Pons in 1818-19. A comet having been then discovered by him, and its elements determined, Encke (from whom the comet has its name) immediately showed that it was the body which had been seen in 1805. Olbers detected it to be the comet of 1795; and Encke (Berlin Ephemeris, 1822 and 1823) having established the fact that its revolution was completed in about 1200 days, predicted approximately the part of the heavens in which it would reappear in 1822. The prediction was verified by the observations of M. Rumker at Parama, since which time it has regularly taken its place as one of the bodies of the solar system.

Upon the question which has been raised relative to the gradual approach of this comet to the sun, and the consequent presumption of the existence of a resisting medium, see COMET. The memoir of M. Encke (translated by Mr. Airy, as cited) enters fully into the discussion of this question.

The elements of this body, adopted by M. Encke for its reappearance in 1832, are as follows:

Passage through perihelion, 1832, May 3.99.
Longitude of perihelion, 157° 21'

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Longitude of ascending node, 334° 32′
Inclination, 13° 22′.

Angle of eccentricity, 57° 43'.

Mean daily sidereal motion, 1071"-1.
Perihelion distance, 3435) Earth's mean distance from
Aphelion distance, 4.1015 sun being unity.
Periodic time, 1210 days.

ENCRINITES, the name by which the petrified radiated animals commonly called Stone Lilies have been long known in Britain; it is frequently applied to the Crinoidea generally, both recent and fossil.

Lamarck arranged the genus Encrinus in his fifth order of Polypes (Polypi natantes), fixing its position between Virgularia and Umbellularia, and recording but two species, one recent, viz. Encrinus Caput Medusæ (Isis Asteria Linn.), from the seas of the Antilles, the other fossil, viz., Encrinus liliformis, Lilium lapideum (Stone Lily) of Ellis and others.

Cuvier included the encrinites among his pedicillated echinoderms, considering that they should be placed near the Comatula; and, in the Règne Animal, they are, accordingly to be found between the great group of the Starfishes and that of the Echinidans.

De Blainville observes that the beautiful work of Guettard (Acad. des Sc. 1755) upon the living and fossil encrinites showed long ago the great relationship which there is between these and the stellerideans, now known under the name of Comatula, and he remarks upon the arrangement of Lamarck, who followed Linnæus and his adherents in placing them among the zoophytes, notwithstanding Guettard's exposition and Ellis's confirmation. After alluding to Miller's work on the family, and to Mr. Thompson's description of the living specimen found on the coast of Ireland, De Blainville takes as the basis of his terminology the parts which exist in Comatula, and adopting the views of Rosinus, rejects that proposed by Miller in his interesting memoir, objecting to the terms pelvis, costal, intercostal scapula, hand, fingers, &c., as derived from animals of an entirely different type of form and inapplicable to the radiated structure.

We find, then, that the pelvis of Miller is the centrodorsal joint (l'article centro-dorsal) of De Blainville. The costal is the first basilary joint of each ray. The intercostal is the second basilary joint. The scapula is the third, or that on which the radii are supported. The hand is the part of the ray which is divided but not separated. The fingers are the digitations or divisions of the rays. Finally, the pinnules are the lateral divisons of the digifations; and De Blainville, like Miller, divides the rays into principal rays and accessory or auxiliary rays.*

Habits, &c. Dr. Buckland (Bridgewater Treatise), who uses the phraseology of Miller, speaks of these animals as destined to find their nourishment by spreading their nets and moving their bodies through a limited space, from a fixed position at the bottom of the sea; or by employing the same instruments, either when floating singly through the water, or attached like Pentelasmis (CIRRIPEDA) to floating pieces of wood. He refers to Miller for several instances of their power of repairing casual injuries, and figures a recent Pentacrinus, one of whose arms is under the process of being reproduced, as crabs and lobsters reproduce their lost claws and legs, and many lizards their tails and feet, observing that the arms of starfishes also, when broken off, are in the same manner reproduced. The same author remarks, that although the representatives of the crinoïdeans in our modern seas are of rare occurrence, this family was of vast numerical importance among the earliest inhabitants of the antient deep. We may judge,' say Dr. Buckland, of the degree to which the individuals of these species multiplied among the first inhabitants of the sea, from the countless myriads of their petrified remains which fill so many limestone-beds of the transition formations, and compose vast strata of entrochal marble, extending over large tracts of country in Northern Europe and North America. The substance of this marble is often almost as entirely made up of the petrified bones of encrinites as a corn-rick is composed of straws. Man applies it to

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It is necessary to put the student on his guard against the confusion and error manifest in this part of M. de Blainville's useful work. This was not a little puzzling when considered as coming from a peu of such high reputation as his; till the arrival of the Nouvelles additions et corrections" brought the information that.' par une transposition singulière du manuscrit, il y a eu une sorte de mélange entre les paragraphes qui appartiennent aux geures Encri nus et Pentacrisus. In short, among other mistakes, the titles Encrinus and Pentacrinus, together with whole paragraphs, have been misplaced. 3 D 2

Description. This appears to be the Astropoda elegans (stem) of Defrance. It is the Bradford Pear Encrinite of Parkinson, and is described by Miller as a Crinoidal animal, with a round column, composed of joints adhering by raenlarge at its apex, sustaining the pelvis, costæ, and scapulæ, from which the arms and tentaculated fingers proceed. Base formed by exuding calcareous matter, which indurates in laminæ, and permanently attaches the animal to extraneous bodies.

construct his palace and adorn his sepulchre, but there are few who know, and fewer still who duly appreciate, the surprising fact, that much of this marble is composed of the skeletons of millions of organized beings, once endowed with life, and susceptible of enjoyment, which, after per-diating surfaces, of which from ten to fourteen gradually forming the part that was for a while assigned to them in living nature, have contributed their remains towards the composition of the mountain masses of the earth. Of more than thirty species of crinoïdeans that prevailed to such enormous extent in the transition period, nearly all became extinct before the deposition of the lias, and only one presents the angular column of the pentacrinite: with this one exception, pentangular columns first began to abound among the crinoïdeans at the commencement of the lias, and have from thence extended onwards into our present seas. Their several species and even genera are also limited in their extent; e. g. the great lily encrinite (E. moniliformis) is peculiar to the muschel-kalk, and the pear encrinite to the middle region of the oolitic formation.'

bræ.

The same author, speaking of the joints which composed the stem, says, the name of Entrochi, or wheelstones, has with much propriety been applied to these insulated verteThe perforations in the centre of these joints affording a facility for stringing them as beads, has caused them in antient times to be used as rosaries. In the northern parts of England they still retain the appellation of St. Cuthbert's beads.

On a rock by Lindisfarn

Saint Cuthbert sits, and toils to frame
The sea-born beads that bear his name.

'Each of these presents a similar series of articulations,
varying as we ascend upwards through the body of the
animal, every joint being exactly adjusted to give the re-
quisite amount of flexibility and strength. From one
extremity of the vertebral column to the other, and through-
out the hands and fingers, the surface of each bone articu-
lates with that adjacent to it, with the most perfect regu-
larity and nicety of adjustment. So exact and methodical
is this arrangement, even to the extremity of its minutest
tentacula, that it is just as improbable that the metals which
compose the wheels of a chronometer should for themselves
have calculated and arranged the form and number of the
teeth of each respective wheel, and that these wheels should
have placed themselves in the precise position fitted to
attain the end resulting from the combined action of them
all, as for the successive hundreds and thousands of little
bones that compose an Encrinite to have arranged them-
selves in a position subordinate to the end produced by the
combined effect of their united mechanism, each acting its
peculiar part in harmonious subordination to the rest; and
all conjointly producing a result which no single series of
them acting separately could possibly have effected.'
(Bridgewater Treatise.)

De Blainville characterizes his Fixed Asterencrinideans (Astérencrinides fixés) as having a body more or less bursiform, supported upon a long articulated stem, and fixed by a radiciform part.

Genera. Apiocrinites.

Miller, who established this genus, characterizes it as an animal with a column gradually enlarging at the apex, composed of numerous joints, of which the superior is marked by five diverging ridges, dividing the surface into as many equal portions, sustaining the pelvis, formed of five sub-cuneiform joints, supporting others of a figure nearly similar, from which proceed the arms and tentaculated fingers formed of simple joints having the figure of a horse-shoe.

De Blainville thus defines it. Body regular, circular, for the rest unknown, contained in a sort of cupule or conical test (têt), composed of three superposed rows, each consisting of five scaphoid plates, united or joined throughout, the upper one supporting on a radiated surface the rays which are formed by a simple series of non-pinnated (?) articulations. Stem round, at first as large as the body, attenuating by degrees down to the root; articulations circular, little elevated, pierced by a round hole, and radiated at their surface. Auxiliary rays scattered.

Locality. (Oolite, middle region.) Bradford in Wiltshire, Abbotsbury, near Weymouth, Dorsetshire, Soissons, Rochelle, &c

Apiocrinites rotundus restored and reduced: 1, expanded; 2, closed: 4 joints of the stem: two young individuals, and the surfaces of two truncated the remedial effect of calcareous secretions in repairing an injury of the stems appear at the base; 3, pear-shaped body of Apiocrinites rotundas, showing at its upper extremity the internal disposition of the bones sur Geological Distribution.-The genus has occurred hi- the cavity of the stomach, and a series of lower cavities, or hollow lenticular rounding the cavity of the stomach; 4, vertical section of the body, showing therto in a fossil state only, and has only been found in spaces, between the central portions of the enlarged joints of the upper portion strata posterior to the lias. Example, Apiocrinites rotun-ments of the alimentary canal, which descends through the axis of the entire of the vertebral column. These spaces are considered by Miller as enlarge Round-columned, Pear-like, Lily-shaped animal column. The surfaces of the joints of the vertebral column are striated sith rays on the adjacent plates, and allow of flexure without risk of dislocation, (Dr.Buckland, Bridgewater Treatise.)

dus.
(Miller).

It will be observed, that De Blainville speaks of the rays as being formed of a simple series of articulations without pinnæ: he adds, it is true, a note of interrogation. Miller in his restoration has made the rays pinnated; and Dr. Buckland, from whose work the cuts above given are by permission taken, has continued Miller's restoration: nor do we see any reason for objecting to the views of the lastnamed authors. The absence of pinnæ on the rays would make the apparatus a very imperfect organ of capture; but the presence of those appendages produces at once the net like structure observable in many others of the family, so admirably adapted for taking and securing the prey which might come within the sphere of the Encrinite's action.*

Miller describes and figures a second species, Apiocrinites ellipticus (Bottle Encrinite, Strait Encrinite, and Stag-Horn Encrinite of Parkinson; Goldfuss refers to it as A. elongatus), and gives the chalk-pits of Wiltshire and Kent as its localities. The bodies, &c., of this species are the Chalk Bottles of the quarrymen.

M. Goldfuss, in his great work, records four additional species, viz. A rosaceus, A. mespiliformis, and A. Milleri (Schlotheim), and A. flexuosus, and A. obconicus (Goldfuss), retaining Miller's A. ellipticus, and referring to Miller's description of that species for A. elongatus also.

Encrinus. (Encrinites, True Lily-shaped animal of Miller.)

Miller characterizes his genus Encrinites as a crinoidal animal, with a column formed of numerous round depressed joints, adhering by a radiating grooved surface, and becoming subpentangular near the pelvis, which is composed of five pieces, giving a lateral insertion to the first series of costal plates, to which the second series and scapula succeed, whence the tentaculated arms or fingers proceed, formed by double series of joints. He observes, that the animals of this genus have not hitherto been found in a living state, nor does he believe that their remains have been discovered in England. Only one species known, viz. Encrinites liliformis of Lamarck.

Description, &c.-This is the Encrinites moniliformis, Bead-columned, True Lily-shaped animal of Miller, who describes the species as a crinoidal animal, with a column formed of numerous round joints, alternately, as they approach the pelvis, larger and smaller, becoming subpentangular when nearly in contact with it. On the pelvis, formed of five pieces, adhere laterally the first series of costa, on which the second series of costa is placed, succeeded by the scapulæ, from which the ten tentaculated arms or fingers proceed. Animal permanently affixed by exuded indurated matter.

We consider his Encrinites moniliformis as the Encrinus liliformis of Lamarck, the Encrine, and Lys de Mer, of the French, the Lilium lapideum of some of the older writers, and the Stone Lily of the English. Locality, (Muschel-kalk) Hildesheim, Rakenberg, near Goslar, Obernscheden and Azzenhausen, not far from Gemenden, in Lower Saxony; Sewerven in Juliers, in Westphalia; the village of Erkerode, in Brunswick, about two miles from the town bearing this name, near a wood called the Elm, &c. In this last-named locality the quarry is on the declivity of a hill overgrown with wood, on which account the inhabitants oppose the digging after them. The stratum containing them is hardly fifteen to eighteen inches in thickness. Under the surface of the earth is a friable, porous, argillaceous limestone, containing millions of columns and columnar joints; but many hours' digging is necessary before a good specimen of the superior part, or stone-lily, can be procured, since the moisture in the stone contributes to their rapid destruction, and their occurring on large pieces of stone makes them liable to separation, which accounts for the many mended specimens. Another and harder stratum under the above contains numerous crinoidal remains; but, according to the quarrymen, no stone lilies. (Miller.) The author last quoted adds that there is good reason to believe that the formation in which the remains are found near Brunswick corresponds with the white lias of England, as it appears to repose on the newer red sandstone, containing salt and gypsum.

stated that the emperor of Germany offered one hundred dollars for a stone lily free from the matrix, and attached to its column.

'The peculiarly fine lily encrinite,' writes Miller, 'figured by Knorr. tab. 11. a, was, it is said, purchased (Naturforscher, Stück 3) from the labourers at the limestone quarry at Schrapland, near Halle, by Inspector Wilkens, for thirtytwo groschen, and given to Professor Lange, who sold it to baron Niegart. However in the same publication (Stück 6), it is stated that it was not bought by Wilkens, but by Mr. Vitigo, at Farrenstadt, near Querfurt, for two dollars, and given to Lange, who sold it for three louis d'or. If my memory does not misgive me, I think I saw the specimen about twenty years ago in the collection of the Naturforschenden Geselschaft, at Danzig. Where is it now?'

Encrinus liliiformis.

Pentacrinus. (Pentacrinites vel Pentacrinus, Five-angled Lily-shaped Animal. Miller. Pentagonites Rafinesque. Fine specimens of this fossil have always been and still The following is Miller's Generic character. An animal are sought for with great eagerness by collectors. In the with a column formed of numerous pentangular joints, artiBeytraege zur Naturgeschichte,' Altenburg, 1774, it is culating by surfaces with pentapetalous semistriated markSines the above was written, we find that M. de Blainville has corrected ings. Superior columnar joint supporting a pelvis of five himself: for, in the Nouvelles Additions et Corrections,' he says, speaking of joints, on which five first costals rest, succeeded by five Apiocrinites, in the characteristic, instead of three, read four,' and add,' rays second costals and five scapulæ, from which ten arms pro

bind to the base, and composed of simply pinnated articulations.'

ceed, having each two hands, composed of several tentacu-issuing from a common base, I conceive that this species lated fingers. Column long, having numerous auxiliary also adhered by a base to extraneous matter. This idea side-arms. Base not ascertained.

Recent species.

Pentacrinus Caput Medusa. Description. A crinoidal animal having a column formed of numerous pentangular joints, articulating by surfaces with pentapetalous, ovate, striated markings; five auxiliary side-arms formed of round joints proceeding from the column at intervals. Superior columnar joints supporting a pelvis of five plates, to which the first costals, second costals, and scapula, succeed, from which ten arms proceed, each supporting two hands, subdividing into three fingers. Lower extremity, or base, unknown. (Miller.)

This is the Encrinus Caput Medusa of Lamarck, Isis Asteria of Linnæus. Locality, the seas of the Antilles. Near the island of Barbadoes (Dr. Hunter's specimen) that of Nevis (specimen formerly belonging to James Tobin, Eq., now in the British Museum)-and Martinique (specimen in the Paris Museum). There is also a specimen in the Museum of the Royal College of Surgeons in London, and one in that of the Geological Society of London.

Pentacrinus Caput Meduse. In the front of the figure two of the arms are much smaller than the others, showing that the animal had suffered mutila tion, and had employed its power of reproducing the lost parts. a. The auxiliary side-arms, articulating at distant intervals with the vertebral column, capable also of being reproduced. (Miller and Buckland.)

gains some further ground, from all the recent specimens hitherto found having broken abruptly off in the endeavour to remove them, as not being able to free themselves from the points of adhesion, which certainly would have been the case had the animal possessed a locomotive power. This inference acquires additional confirmation from the obser vations made by the late J. Tobin, Esq., on another speci men, viz. Some years ago I was in possession of a larger Pentacrinite, which was brought to me so fresh out of the sea that at the bottom (where it plainly appeared to have been broken off from the rock to which it was fixed) the blood was actually oozing from the vertebræ. This speci men I endeavoured to preserve, but it was totally destroyed by the ants, who ate every cartilage, so that it fell to pieces.' Miller observes upon this, that the blood' was the fluid in the alimentary canal, and refusing to admit the assertion of Walch, that the Pentacrinite is an animal crawling along the bottom of the sea, conceives it to have generally stood more or less erect in the sea, yielding to the fury of the storm in bending down, and adhering for additional security with its side-arms to extraneous matter, or closing them to the column, and thus offering the least surface possible to the element. The latter, he thinks, is the most probable idea, since he had frequently met with specimens in that state, but had never seen any side-arms clasping round extraneous matter. The author elsewhere states that he has in vain endeavoured to trace apertures at the terminating points of the fingers and tentacula, although Guettard alleges that here orifices existed serving as mouths to the animal in taking its food.

Miller observes that columnar fragments, smaller and rather neater than those of this species, occur in the oolite at Dundry, the forest marble at Chippenham, and the chalk near Lyme, but that it remains to be ascertained, by the acquisition of perfect specimens, whether these belong to a variety of P. Caput Medusa, or possess peculiar characters sufficient to distinguish them as a new species.

[graphic]

FOSSIL SPECIES.

We select, as an example, the Briarean Pentacrinite, Pentacrinus Briareus, thus characterized by Miller. 'A crinoidal animal, having a large column formed of numerous pentagonal joints, alternately larger and smaller, articu lating by surfaces with pentapetalous compressed semistriated markings; five auxiliary arms, formed of much compressed suboval joints, proceeding at intervals from the column; five joints of the pelvis, supporting five first and five second costal joints, on which the scapulae affix, from which ten arms proceed, each having two hands, formed of numerous fingers, sometimes amounting to sixteen.'

Dr. Buckland observes that the root of the Briarean Pentacrinite was probably slight, and capable of being withdrawn from its attachment. The absence of any large solid secretions like those of the Pear Encrinite, by which this Pentacrinite could have been fixed permanently at the bottom, and the further fact of its being frequently found in contact with masses of drifted wood converted into jet, leads him to infer that the Briarean Pentacrinite was a locomotive animal, having the power of attaching itself temporarily either to extraneous floating bodies or to rocks at the bottom of the sea, either by its side-arms or by a moveable articulated small root. We confess that we cannot entirely concur with the professor on this point. That in early youth the animal may have floated till it found a substance fit for it to adhere to, we do not deny; but we think that after it was once established and had attained a good size, it was fixed for ever. The great length of the Mr. Miller, in speaking of Mr. Tobin's specimen, says, stem and the numerous side-arms must have secured for it In the drawing it up from the bottom of the sea, the a field of action beyond that of the Pear Encrinite and the animal has clearly been broken off, leaving its posterior Lily Encrinite, both of which we know had permanent portion behind; thus we have lost the chance of ascertain-roots; and if we are to judge by analogy, there is pregnant ing the fact, whether it adhered by a fixed base, or had a locomotive power. The same accident has befallen the other recent individuals that have been mentioned when speaking of the locality of this species. However, judging from its analogy to the Encrinus moniliformis, from its long column, numerous auxiliary side-arms, and the associated manner in which groups of the following species are sometimes found preserved on the surface of a single slab, with the columns all tending towards the same point, as if

evidence that the specimens of the living species, more especially the larger one mentioned by Mr. Tobin, who saw it quite fresh out of the sea, and to whose expressions above given we refer the reader, suffered their stems to be torn asunder without quitting their moorings.

Locality.-Lower strata of the oolite formation, especially the Lias: Lyme, Watchet, Keynsham, &c.

angularis, P. basaltiformis, and P. tuberculatus. Goldfuss Mr. Miller gives three other fossil species, viz., P. sub

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