Chapter XX: Part 20

LAMBESSA, the ancient Lambaesa, a village of Algeria, in the arrondissement of Batna and department of Constantine, 7 m. S.E. of Batna and 17 W. of Timgad. The modern village, the centre of an agricultural colony founded in 1848, is noteworthy for its great convict establishment (built about 1850). The remains of the Roman town, and more especially of the Roman camp, in spite of wanton vandalism, are among the most interesting ruins in northern Africa. They are now preserved by the _Service des Monuments historiques_ and excavations have resulted in many interesting discoveries. The ruins are situated on the lower terraces of the Jebel Aures, and consist of triumphal arches (one to Septimius Severus, another to Commodus), temples, aqueducts, vestiges of an amphitheatre, baths and an immense quantity of masonry belonging to private houses. To the north and east lie extensive cemeteries with the stones standing in their original alignments; to the west is a similar area, from which, however, the stones have been largely removed for building the modern village. Of the temple of Aesculapius only one column is standing, though in the middle of the 19th century its façade was entire. The capitol or temple dedicated to Jupiter, Juno and Minerva, which has been cleared of débris, has a portico with eight columns. On level ground about two-thirds of a mile from the centre of the ancient town stands the camp, its site now partly occupied by the penitentiary and its gardens. It measures 1640 ft. N. to S. by 1476 ft. E. to W., and in the middle rise the ruins of a building commonly called, but incorrectly, the praetorium. This noble building, which dates from A.D. 268, is 92 ft. long by 66 ft. broad and 49 ft. high; its southern façade has a splendid peristyle half the height of the wall, consisting of a front row of massive Ionic columns and an engaged row of Corinthian pilasters. Behind this building (which was roofed), is a large court giving access to other buildings, one being the arsenal. In it have been found many thousands of projectiles. To the S.E. are the remains of the baths. The ruins of both city and camp have yielded many inscriptions (Renier edited 1500, and there are 4185 in the _Corpus Inscr. Lat._ vol. viii.); and, though a very large proportion are epitaphs of the barest kind, the more important pieces supply an outline of the history of the place. Over 2500 inscriptions relating to the camp have been deciphered. In a museum in the village are objects of antiquity discovered in the vicinity. Besides inscriptions, statues, &c., are some fine mosaics found in 1905 near the arch of Septimius Severus. The statues include those of Aesculapius and Hygieia, taken from the temple of Aesculapius.

Lambaesa was a military foundation. The camp of the third legion
(Legio III. Augusta), to which it owes its origin, appears to have
been established between A.D. 123 and 129, in the time of Hadrian,
whose address to his soldiers was found inscribed on a pillar in a
second camp to the west of the great camp still extant. By 166 mention
is made of the decurions of a vicus, 10 curiae of which are known by
name; and the vicus became a municipium probably at the time when it
was made the capital of the newly founded province of Numidia. The
legion was removed by Gordianus, but restored by Valerianus and
Gallienus; and its final departure did not take place till after 392.
The town soon afterwards declined. It never became the seat of a
bishop, and no Christian inscriptions have been found among the ruins.

About 2 m. S. of Lambessa are the ruins of Markuna, the ancient
Verecunda, including two triumphal arches.

See S. Gsell, _Les Monuments antiques de l'Algérie_ (Paris, 1901) and
_L'Algérie dans l'antiquité_ (Algiers, 1903); L. Renier, _Inscriptions
romaines de l'Algérie_ (Paris, 1855); Gustav Wilmann, "Die röm.
Lagerstadt Afrikas," in _Commentationes phil. in honorem Th. Mommseni_
(Berlin, 1877); Sir L. Playfair, _Travels in the Footsteps of Bruce_
(London, 1877); A. Graham, _Roman Africa_ (London, 1902).

LAMBETH, a southern metropolitan borough of London, England, bounded N.W. by the river Thames, N.E. by Southwark, E. by Camberwell and W. by Wandsworth and Battersea, and extending S. to the boundary of the county of London. Pop. (1901) 301,895. The name is commonly confined to the northern part of the borough, bordering the river; but the principal districts included are Kennington and Vauxhall (north central), Brixton (central) and part of Norwood (south). Four road-bridges cross the Thames within the limits of the borough, namely Waterloo, Westminster, Lambeth and Vauxhall, of which the first, a fine stone structure, dates from 1817, and is the oldest Thames bridge standing within the county of London. The main thoroughfare runs S. from Westminster Bridge Road as Kennington Road, continuing as Brixton Road and Brixton Hill, Clapham Road branching S.W. from it at Kennington. Several thoroughfares also converge upon Vauxhall Bridge, and from a point near this down to Westminster Bridge the river is bordered by the fine Albert Embankment.

Early records present the name _Lamb-hythe_ in various forms. The suffix is common along the river in the meaning of a haven, but the prefix is less clear; a Saxon word signifying mud is suggested. Brixton and Kennington are mentioned in Domesday; and in Vauxhall is concealed the name of Falkes de Breauté, an unscrupulous adventurer of the time of John and Henry III. exiled in 1225. The manor of North Lambeth was given to the bishopric of Rochester in the time of Edward the Confessor, and the bishops had a house here till the 16th century. They did not, however, retain the manor beyond the close of the 12th century, when it was acquired by the see of Canterbury. The palace of the archbishops is still here, and forms, with the parish church, a picturesque group of buildings, lying close to the river opposite the majestic Houses of Parliament, and to some extent joining with them to make of this reach of the Thames one of the finest prospects in London. The oldest part of the palace remaining is the Early English chapel. The so-called Lollard's Tower, which retains evidence of its use as a prison, dates c. 1440. There is a fine Tudor gatehouse of brick, and the hall is dated 1663. The portion now inhabited by the archbishops was erected in 1834 and fronts a spacious quadrangle. Among the portraits of the archbishops here are examples by Holbein, Van Dyck, Hogarth and Reynolds. There is a valuable library. The church of St Mary was rebuilt c. 1850, though the ancient monuments preserved give it an appearance of antiquity. Here are tombs of some of the archbishops, including Bancroft (d. 1610), and of the two Tradescants, collectors, and a memorial to Elias Ashmole, whose name is preserved in the Ashmolean Museum at Oxford University, to which he presented the collections of his friend the younger Tradescant (d. 1662). In the present Westminster Bridge Road was a circus, well known in the later 18th and early 19th centuries as Astley's, and near Vauxhall Bridge were the celebrated Vauxhall Gardens.

The principal modern pleasure grounds are Kennington Park (20 acres),
and Brockwell Park (127 acres) south of Brixton, and near the southern
end of Kennington Road is Kennington Oval, the ground of the Surrey
County Cricket Club, the scene of its home matches and of other
important fixtures. Among institutions the principal is St Thomas'
Hospital, the extensive buildings of which front the Albert
Embankment. The original foundation dated from 1213, was situated in
Southwark, and was connected with the priory of Bermondsey. The
existing buildings, subsequently enlarged, were opened in 1871, are
divided into a series of blocks, and include a medical school. Other
hospitals are the Royal, for children and women, Waterloo Road, the
Lying-in Hospital, York Road, and the South-western fever hospital in
Stockwell. There are technical institutes in Brixton and Norwood; and
on Brixton Hill is Brixton Prison. In the northern part of the borough
are numerous factories, including the great Doulton pottery works. The
parliamentary borough of Lambeth has four divisions, North,
Kennington, Brixton and Norwood, each returning one member. The
borough council consists of a mayor, 10 aldermen and 60 councillors.
Area, 4080.4 acres.

LAMBETH CONFERENCES, the name given to the periodical assemblies of bishops of the Anglican Communion (Pan-Anglican synods), which since 1867 have met at Lambeth Palace, the London residence of the archbishop of Canterbury. The idea of these meetings was first suggested in a letter to the archbishop of Canterbury by Bishop Hopkins of Vermont in 1851, but the immediate impulse came from the colonial Church in Canada. In 1865 the synod of that province, in an urgent letter to the archbishop of Canterbury (Dr Longley), represented the unsettlement of members of the Canadian Church caused by recent legal decisions of the Privy Council, and their alarm lest the revived action of Convocation "should leave us governed by canons different from those in force in England and Ireland, and thus cause us to drift into the status of an independent branch of the Catholic Church." They therefore requested him to call a "national synod of the bishops of the Anglican Church at home and abroad," to meet under his leadership. After consulting both houses of the Convocation of Canterbury, Archbishop Longley assented, and convened all the bishops of the Anglican Communion (then 144 in number) to meet at Lambeth in 1867. Many Anglican bishops (amongst them the archbishop of York and most of his suffragans) felt so doubtful as to the wisdom of such an assembly that they refused to attend it, and Dean Stanley declined to allow Westminster Abbey to be used for the closing service, giving as his reasons the partial character of the assembly, uncertainty as to the effect of its measures and "the presence of prelates not belonging to our Church." Archbishop Longley said in his opening address, however, that they had no desire to assume "the functions of a general synod of all the churches in full communion with the Church of England," but merely to "discuss matters of practical interest, and pronounce what we deem expedient in resolutions which may serve as safe guides to future action." Experience has shown how valuable and wise this course was. The resolutions of the Lambeth Conferences have never been regarded as synodical decrees, but their weight has increased with each conference. Apprehensions such as those which possessed the mind of Dean Stanley have long passed away.

Seventy-six bishops accepted the primate's invitation to the first conference, which met at Lambeth on the 24th of September 1867, and sat for four days, the sessions being in private. The archbishop opened the conference with an address: deliberation followed; committees were appointed to report on special questions; resolutions were adopted, and an encyclical letter was addressed to the faithful of the Anglican Communion. Each of the subsequent conferences has been first received in Canterbury cathedral and addressed by the archbishop from the chair of St Augustine. It has then met at Lambeth, and after sitting for five days for deliberation upon the fixed subjects and appointment of committees, has adjourned, to meet again at the end of a fortnight and sit for five days more, to receive reports, adopt resolutions and to put forth the encyclical letter.

I. _First Conference_ (September 24-28, 1867), convened and presided
over by Archbishop Longley. The proposed order of subjects was
entirely altered in view of the Colenso case, for which urgency was
claimed; and most of the time was spent in discussing it. Of the
thirteen resolutions adopted by the conference, two have direct
reference to this case; the rest have to do with the creation of new
sees and missionary jurisdictions, commendatory letters, and a
"voluntary spiritual tribunal" in cases of doctrine and the due
subordination of synods. The reports of the committees were not ready,
and were carried forward to the conference of 1878.

II. _Second Conference_ (July 2-27, 1878), convened and presided over
by Archbishop Tait. On this occasion no hesitation appears to have
been felt; 100 bishops were present, and the opening sermon was
preached by the archbishop of York. The reports of the five special
committees (based in part upon those of the committee of 1867) were
embodied in the encyclical letter, viz. on the best mode of
maintaining union, voluntary boards of arbitration, missionary bishops
and missionaries, continental chaplains and the report of a committee
on difficulties submitted to the conference.

III. _Third Conference_ (July 3-27, 1888), convened and presided over
by Archbishop Benson; 145 bishops present; the chief subject of
consideration being the position of communities which do not possess
the historic episcopate. In addition to the encyclical letter,
nineteen resolutions were put forth, and the reports of twelve special
committees are appended upon which they are based, the subjects being
intemperance, purity, divorce, polygamy, observance of Sunday,
socialism, care of emigrants, mutual relations of dioceses of the
Anglican Communion, home reunion, Scandinavian Church, Old Catholics,
&c., Eastern Churches, standards of doctrine and worship. Perhaps the
most important of these is the famous "Lambeth Quadrilateral," which
laid down a fourfold basis for home reunion--the Holy Scriptures, the
Apostles' and Nicene creeds, the two sacraments ordained by Christ
himself and the historic episcopate.

IV. _Fourth Conference_ (July 5-31, 1897), convened by Archbishop
Benson, presided over by Archbishop Temple; 194 bishops present. One
of the chief subjects for consideration was the creation of a
"tribunal of reference"; but the resolutions on this subject were
withdrawn, owing, it is said, to the opposition of the American
bishops, and a more general resolution in favour of a "consultative
body" was substituted. The encyclical letter is accompanied by
sixty-three resolutions (which include careful provision for
provincial organization and the extension of the title "archbishop" to
all metropolitans, a "thankful recognition of the revival of
brotherhoods and sisterhoods, and of the office of deaconess," and a
desire to promote friendly relations with the Eastern Churches and the
various Old Catholic bodies), and the reports of the eleven committees
are subjoined.

V. _Fifth Conference_ (July 6-August 5, 1908), convened by Archbishop
Randall Davidson, who presided; 241 bishops were present. The chief
subjects of discussion were: the relations of faith and modern
thought, the supply and training of the clergy, education, foreign
missions, revision and "enrichment" of the Prayer-Book, the relation
of the Church to "ministries of healing" (Christian Science, &c.), the
questions of marriage and divorce, organization of the Anglican
Church, reunion with other Churches. The results of the deliberations
were embodied in seventy-eight resolutions, which were appended to the
encyclical issued, in the name of the conference, by the Archbishop of
Canterbury on the 8th of August.

The fifth Lambeth conference, following as it did close on the great
Pan-Anglican congress, is remarkable mainly as a proof of the growth
of the influence and many-sided activity of the Anglican Church, and
as a conspicuous manifestation of her characteristic principles. Of
the seventy-eight resolutions none is in any sense epoch-making, and
their spirit is that of the traditional Anglican _via media_. In
general they are characterized by a firm adherence to the fundamental
articles of Catholic orthodoxy, tempered by a tolerant attitude
towards those not of "the household of the faith." The report of the
committee on faith and modern thought is "a faithful attempt to show
how the claim of our Lord Jesus Christ, which the Church is set to
present to each generation, may, under the characteristic conditions
of our time, best command allegiance." On the question of education
(Res. 11-19) the conference reaffirmed strongly the necessity for
definite Christian teaching in schools, "secular systems" being
condemned as "educationally as well as morally unsound, since they
fail to co-ordinate the training of the whole nature of the child"
(Res. 11). The resolutions on questions affecting foreign missions
(20-26) deal with e.g. the overlapping of episcopal jurisdictions (22)
and the establishment of Churches on lines of race or colour, which is
condemned (20). The resolutions on questions of marriage and divorce
(37-43) reaffirm the traditional attitude of the Church; it is,
however, interesting to note that the resolution (40) deprecating the
remarriage in church of the innocent party to a divorce was carried
only by eighty-seven votes to eighty-four. In resolutions 44 to 53 the
conference deals with the duty of the Church towards modern democratic
ideals and social problems; affirms the responsibility of investors
for the character and conditions of the concerns in which their money
is placed (49); "while frankly acknowledging the moral gains sometimes
won by war" strongly supports the extension of international
arbitration (52); and emphasizes the duty of a stricter observance of
Sunday (53). On the question of reunion, the ideal of corporate unity
was reaffirmed (58). It was decided to send a deputation of bishops
with a letter of greeting to the national council of the Russian
Church about to be assembled (60) and certain conditions were laid
down for inter-communion with certain of the Churches of the Orthodox
Eastern Communion (62) and the "ancient separated Churches of the
East" (63-65). Resolution 67 warned Anglicans from contracting
marriages, under actual conditions, with Roman Catholics. By
resolution 68 the conference stated its desire to "maintain and
strengthen the friendly relations" between the Churches of the
Anglican Communion and "the ancient Church of Holland" (Jansenist, see
UTRECHT) and the old Catholic Churches; and resolutions 70-73 made
elaborate provisions for a projected corporate union between the
Anglican Church and the _Unitas Fratrum_ (Moravian Brethren). As to
"home reunion," however, it was made perfectly clear that this would
only be possible "on lines suggested by such precedents as those of
1610," i.e. by the Presbyterian Churches accepting the episcopal
model. So far as the organization of the Anglican Church is concerned,
the most important outcome of the conference was the reconstruction of
the Central Consultative Body on representative lines (54-56); this
body to consist of the archbishop of Canterbury and seventeen bishops
appointed by the various Churches of the Anglican Communion throughout
the world. A notable feature of the conference was the presence of the
Swedish bishop of Kalmar, who presented a letter from the archbishop
of Upsala, as a tentative advance towards closer relations between the
Anglican Church and the Evangelical Church of Sweden.

See Archbishop R. T. Davidson, _The Lambeth Conferences of 1867, 1878
and 1888_ (London, 1896); _Conference of Bishops of the Anglican
Communion, Encyclical Letter_, &c. (London, 1897 and 1908).

LAMBINUS, DIONYSIUS, the Latinized name of DENIS LAMBIN (1520-1572), French classical scholar, born at Montreuil-sur-mer in Picardy. Having devoted several years to classical studies during a residence in Italy, he was invited to Paris in 1650 to fill the professorship of Latin in the Collège de France, which he soon afterwards exchanged for that of Greek. His lectures were frequently interrupted by his ill-health and the religious disturbances of the time. His death (September 1572) is said to have been caused by his apprehension that he might share the fate of his friend Peter Ramus (Pierre de la Ramée), who had been killed in the massacre of St Bartholomew. Lambinus was one of the greatest scholars of his age, and his editions of classical authors are still useful. In textual criticism he was a conservative, but by no means a slavish one; indeed, his opponents accused him of rashness in emendation. His chief defect is that he refers vaguely to his MSS. without specifying the source of his readings, so that their relative importance cannot be estimated. But his commentaries, with their wealth of illustration and parallel passages, are a mine of information. In the opinion of the best scholars, he preserved the happy mean in his annotations, although his own countrymen have coined the word _lambiner_ to express trifling and diffuseness.

His chief editions are: Horace (1561); Lucretius (1564), on which see
H. A. J. Munro's preface to his edition; Cicero (1566); Cornelius
Nepos (1569); Demosthenes (1570), completing the unfinished work of
Guillaume Morel; Plautus (1576).

See Peter Lazer, _De Dionysio Lambino narratio_, printed in Orelli's
_Onomasticon Tullianum_ (i. 1836), and _Trium disertissimorum virorum
praefationes ac epistolae familiares aliquot: Mureti, Lambini, Regii_
(Paris, 1579); also Sandys, _Hist. of Classical Scholarship_ (1908,
ii. 188), and A. Horawitz in Ersch and Gruber's _Allgemeine
Encyclopädie_.

LAMBOURN, a market town in the Newbury parliamentary division of Berkshire, England, 65 m. W. of London, the terminus of the Lambourn Valley light railway from Newbury. Pop. (1901) 2071. It lies high up the narrow valley of the Lambourn, a tributary of the Kennet famous for its trout-fishing, among the Berkshire Downs. The church of St Michael is cruciform and principally late Norman, but has numerous additions of later periods and has been considerably altered by modern restoration. The inmates of an almshouse founded by John Estbury, _c._ 1500, by his desire still hold service daily at his tomb in the church. A Perpendicular market-cross stands without the church. The town has agricultural trade, but its chief importance is derived from large training stables in the neighbourhood. To the north of the town is a large group of _tumuli_ known as the Seven Barrows, ascertained by excavation to be a British burial-place.

LAMECH [Hebrew: Lemech], the biblical patriarch, appears in each of the antediluvian genealogies, Gen. iv. 16-24 J., and Gen. v. P. In the former he is a descendant of Cain, and through his sons the author of primitive civilization; in the latter he is the father of Noah. But it is now generally held that these two genealogies are variant adaptations of the Babylonian list of primitive kings (see ENOCH). It is doubtful whether Lamech is to be identified with the name of any one of these kings; he may have been introduced into the genealogy from another tradition.

In the older narrative in Gen. iv. Lamech's family are the originators of various advances in civilization; he himself is the first to marry more than one wife, 'Adah ("ornament," perhaps specially "dawn") and Zillah ("shadow"). He has three sons Jabal, Jubal, and Tubal, the last-named qualified by the addition of Cain (= "smith"[1]). The assonance of these names is probably intentional, cf. the brothers Hasan and Hosein of early Mahommedan history. Jabal institutes the life of nomadic shepherds, Jubal is the inventor of music, Tubal-Cain the first smith. Jabal and Jubal may be forms of a root used in Hebrew and Phoenician for ram and ram's horn (i.e. trumpet), and underlying our "jubilee." Tubal may be the eponymous ancestor of the people of that name mentioned in Ezekiel in connexion with "vessels of bronze."[2] All three names are sometimes derived from [Hebrew: yuval] in the sense of offspring, so that they would be three different words for "son," and there are numerous other theories as to their etymology. Lamech has also a daughter Naamah ("gracious," "pleasant," "comely"; cf. No'mân, a name of the deity Adonis). This narrative clearly intends to account for the origin of these various arts as they existed in the narrator's time; it is not likely that he thought of these discoveries as separated from his own age by a universal flood; nor does the tone of the narrative suggest that the primitive tradition thought of these pioneers of civilization as members of an accursed family. Probably the passage was originally independent of the document which told of Cain and Abel and of the Flood; Jabal may be a variant of Abel. An ancient poem is connected with this genealogy:

"Adah and Zillah, hear my voice;
Ye wives of Lamech, give ear unto my speech.
I slay a man for a wound,
A young man for a stroke;
For Cain's vengeance is sevenfold,
But Lamech's seventy-fold and seven."

In view of the connexion, the poem is interpreted as expressing Lamech's exultation at the advantage he expects to derive from Tubal-Cain's new inventions; the worker in bronze will forge for him new and formidable weapons, so that he will be able to take signal vengeance for the least injury. But the poem probably had originally nothing to do with the genealogy. It may have been a piece of folk-song celebrating the prowess of the tribe of Lamech; or it may have had some relation to a story of Cain and Abel in which Cain was a hero and not a villain.

The genealogy in Gen. v. belongs to the Priestly Code, _c._ 450 B.C., and may be due to a revision of ancient tradition in the light of Babylonian archaeology. It is noteworthy that according to the numbers in the Samaritan MSS. Lamech dies in the year of the Flood.

The origin of the name Lamech and its original meaning are doubtful.
It was probably the name of a tribe or deity, or both. According to C.
J. Ball,[3] Lamech is an adaptation of the Babylonian _Lamga_, a title
of Sin the moon god, and synonymous with _Ubara_ in the name
Ubara-Tutu, the Otiartes of Berossus, who is the ninth of the ten
primitive Babylonian kings, and the father of the hero of the
Babylonian flood story, just as Lamech is the ninth patriarch, and the
father of Noah. Spurrell[4] states that Lamech cannot be explained
from the Hebrew, but may possibly be connected with the Arabic
_yalmakun_, "a strong young man."

Outside of Genesis, Lamech is only mentioned in the Bible in 1 Chron.
i. 3, Luke iii. 36. Later Jewish tradition expanded and interpreted
the story in its usual fashion. (W. H. Be.)

FOOTNOTES:

[1] The text of Gen. iv. 22 is partly corrupt; and it is possible
that the text used by the Septuagint did not contain Cain.

[2] Gen. x. 2, Ezek. xxvii. 13.

[3] _Genesis_, in Haupt's _Sacred Books of the Old Testament_ on iv.
19, cf. also the notes on 20-22, for Lamech's family. The
identification of Lamech with _Lamga_ is also suggested by Sayce,
_Expository Times_, vii. 367. Cf. also Cheyne, "Cainites" in _Encyc.
Biblica_.

[4] _Notes on the Hebrew Text of Genesis, in loco._

LAMEGO, a city of northern Portugal, in the district of Vizeu and formerly included in the province of Beira; 6 m. by road S. of the river Douro and 42 m. E. of Oporto. Pop. (1900) 9471. The nearest railway station is Peso da Regoa, on the opposite side of the Douro and on the Barca d'Alva-Oporto railway. Lamego is an ancient and picturesque city, in the midst of a beautiful mountain region. Its principal buildings are the 14th-century Gothic cathedral, Moorish citadel, Roman baths and a church which occupies the site of a mosque, and, though intrinsically commonplace, is celebrated in Portugal as the seat of the legendary cortes of 1143 or 1144 (see PORTUGAL, _History_). The principal industries are viticulture and the rearing of swine, which furnish the so-called "Lisbon hams." Lamego was a Moorish frontier fortress of some importance in the 9th and 10th centuries. It was captured in 1057 by Ferdinand I. of Castile and Leon.

LAMELLIBRANCHIA (Lat. _lamella_, a small or thin plate, and Gr. [Greek: branchia], gills), the fourth of the five classes of animals constituting the phylum Mollusca (q.v.). The Lamellibranchia are mainly characterized by the rudimentary condition of the head, and the retention of the primitive bilateral symmetry, the latter feature being accentuated by the lateral compression of the body and the development of the shell as two bilaterally symmetrical plates or valves covering each one side of the animal. The foot is commonly a simple cylindrical or ploughshare-shaped organ, used for boring in sand and mud, and more rarely presents a crawling disk similar to that of Gastropoda; in some forms it is aborted. The paired ctenidia are very greatly developed right and left of the elongated body, and form the most prominent organ of the group. Their function is chiefly not respiratory but nutritive, since it is by the currents produced by their ciliated surface that food-particles are brought to the feebly-developed mouth and buccal cavity.

The Lamellibranchia present as a whole a somewhat uniform structure. The chief points in which they vary are--(1) in the structure of the ctenidia or branchial plates; (2) in the presence of one or of two chief muscles, the fibres of which run across the animal's body from one valve of the shell to the other (adductors); (3) in the greater or less elaboration of the posterior portion of the mantle-skirt so as to form a pair of tubes, by one of which water is introduced into the sub-pallial chamber, whilst by the other it is expelled; (4) in the perfect or deficient symmetry of the two valves of the shell and the connected soft parts, as compared with one another; (5) in the development of the foot as a disk-like crawling organ (_Arca_, _Nucula_, _Pectunculus_, _Trigonia_, _Lepton_, _Galeomma_), as a simple plough-like or tongue-shaped organ (_Unionidae_, &c.), as a re-curved saltatory organ (_Cardium_, &c.), as a long burrowing cylinder (_Solenidae_, &c.), or its partial (Mytilacea) or even complete abortion (Ostraeacea).

The essential Molluscan organs are, with these exceptions, uniformly well developed. The mantle-skirt is always long, and hides the rest of the animal from view, its dependent margins meeting in the middle line below the ventral surface when the animal is retracted; it is, as it were, slit in the median line before and behind so as to form two flaps, a right and a left; on these the right and the left calcareous valves of the shell are borne respectively, connected by an uncalcified part of the shell called the ligament. In many embryo Lamellibranchs a centro-dorsal primitive shell-gland or follicle has been detected. The mouth lies in the median line anteriorly, the anus in the median line posteriorly.

Both ctenidia, right and left, are invariably present, the axis of each taking origin from the side of the body as in the schematic archi-Mollusc (see fig. 15). A pair of renal tubes opening right and left, rather far forward on the sides of the body, are always present. Each opens by its internal extremity into the pericardium. A pair of genital apertures, connected by genital ducts with the paired gonads, are found right and left near the nephridial pores, except in a few cases where the genital duct joins that of the renal organ (_Spondylus_). The sexes are often, but not always, distinct. No accessory glands or copulatory organs are ever present in Lamellibranchs. The ctenidia often act as brood-pouches.

A dorsal contractile heart, with symmetrical right and left auricles receiving aerated blood from the ctenidia and mantle-skirt, is present, being unequally developed only in those few forms which are inequivalve. The typical pericardium is well developed. It, as in other Mollusca, is not a blood-space but develops from the coelom, and it communicates with the exterior by the pair of renal tubes. As in Cephalopoda (and possibly other Mollusca) water can be introduced through the nephridia into this space. The alimentary canal keeps very nearly to the median vertical plane whilst exhibiting a number of flexures and loopings in this plane. A pair of large glandular outgrowths, the so-called "liver" or great digestive gland, exists as in other Molluscs. A pair of pedal otocysts, and a pair of osphradia at the base of the gills, appear to be always present. A typical nervous system is present (fig. 19), consisting of a cerebro-pleural ganglion-pair, united by connectives to a pedal ganglion-pair and a visceral ganglion-pair (parieto-splanchnic).

A pyloric caecum connected with the stomach is commonly found, containing a tough flexible cylinder of transparent cartilaginous appearance, called the "crystalline style" (_Mactra_). In many Lamellibranchs a gland is found on the hinder surface of the foot in the mid line, which secretes a substance which sets into the form of threads--the so-called "byssus"--by means of which the animal can fix itself. Sometimes this gland is found in the young and not in the adult (_Anodonta_, _Unio_, _Cyclas_). In some Lamellibranchs (_Pecten_, _Spondylus_, _Pholas_, _Mactra_, _Tellina_, _Pectunculus_, _Galeomma_, &c.), although cephalic eyes are generally absent, special eyes are developed on the free margin of the mantle-skirt, apparently by the modification of tentacles commonly found there. There are no pores in the foot or elsewhere in Lamellibranchia by which water can pass into and out of the vascular system, as formerly asserted.

The Lamellibranchia live chiefly in the sea, some in fresh waters. A very few have the power of swimming by opening and shutting the valves of the shell (_Pecten_, _Lima_); most can crawl slowly or burrow rapidly; others are, when adult, permanently fixed to stones or rocks either by the shell or the byssus. In development some Lamellibranchia pass through a free-swimming trochosphere stage with pre-oral ciliated band; other fresh-water forms which carry the young in brood-pouches formed by the ctenidia have suppressed this larval phase.

Letters in all the figures as follows:

a, Centro-dorsal area.
b, Margin of the left mantle-flap.
c, Margin of the right mantle-flap.
d, Excurrent siphonal notch of the mantle margin.
e, Incurrent siphonal notch of the mantle margin.
f, Foot.
g, Probe passed into the superior division of the sub-pallial chamber
through the excurrent siphonal notch, and issuing by the side of the
foot into the inferior division of the sub-pallial chamber.
h, Anterior (pallial) adductor muscle of the shells.
i, Anterior retractor muscle of the foot.
k, Protractor muscle of the foot.
l, Posterior (pedal) adductor muscle of the shells.
m, Posterior retractor muscle of the foot.
n, Anterior labial tentacle.
o, Posterior labial tentacle.
p, Base-line of origin of the reflected mantle-flap from the side of
the body.
q, Left external gill-plate.
r, Left internal gill-plate.
rr, Internal lamella of the right inner gill-plate.
rg, Right outer gill-plate.
s, Line of concrescence of the outer lamella of the left outer
gill-plate with the left mantle-flap.
t, Pallial tentacles.
u, The thickened muscular pallial margin which adheres to the shell
and forms the pallial line of the left side.
v, That of the right side.
w, The mouth.
x, Aperture of the left organ of Bojanus (nephridium) exposed by
cutting the attachment of the inner lamella of the inner gill-plate.
y, Aperture of the genital duct.
z, Fissure between the free edge of the inner lamella of the inner
gill-plate and the side of the foot, through which the probe g passes
into the upper division of the sub-pallial space.
aa, Line of concrescence of the inner lamella of the right inner
gill-plate with the inner lamella of the left inner gill-plate.
ab, ac, ad, Three pit-like depressions in the median line of the foot
supposed by some writers to be pores admitting water into the vascular
system.
ae, Left shell valve.
af, Space occupied by liver.
ag, Space occupied by gonad.
ah, Muscular substance of the foot.
ai, Duct of the liver on the wall of the stomach.
ak, Stomach.
al, Rectum traversing the ventricle of the heart.
am, Pericardium.
an, Glandular portion of the left nephridium.
ap, Ventricle of the heart.
aq, Aperture by which the left auricle joins the ventricle.
ar, Non-glandular portion of the left nephridium.
as, Anus.
at, Pore leading from the pericardium into the glandular sac of the
left nephridium.
au, Pore leading from the glandular into the non-glandular portion of
the left nephridium.
av, Internal pore leading from the non-glandular portion of the left
nephridium to the external pore x.
aw, Left cerebro-pleuro-visceral ganglion.
ax, Left pedal ganglion.
ay, Left otocyst.
az, Left olfactory ganglion (parieto-splanchnic).
bb, Floor of the pericardium separating that space from the
non-glandular portion of the nephridia.]

As an example of the organization of a Lamellibranch, we shall review the structure of the common pond-mussel or swan mussel (_Anodonta cygnea_), comparing it with other Lamellibranchia.

The swan-mussel has superficially a perfectly developed bilateral
symmetry. The left side of the animal is seen as when removed from its
shell in fig. 1 (1). The valves of the shell have been removed by
severing their adhesions to the muscular areae h, i, k, l, m, u. The
free edge of the left half of the mantle-skirt b is represented as a
little contracted in order to show the exactly similar free edge of
the right half of the mantle-skirt c. These edges are not attached to,
although they touch, one another; each flap (right or left) can be
freely thrown back in the way carried out in fig. 1 (3) for that of
the left side. This is not always the case with Lamellibranchs; there
is in the group a tendency for the corresponding edges of the
mantle-skirt to fuse together by concrescence, and so to form a more
or less completely closed bag, as in the Scaphopoda (_Dentalium_). In
this way the notches d, e of the hinder part of the mantle-skirt of
_Anodonta_ are in the siphonate forms converted into two separate
holes, the edges of the mantle being elsewhere fused together along
this hinder margin. Further than this, the part of the mantle-skirt
bounding the two holes is frequently drawn out so as to form a pair of
tubes which project from the shell (figs. 8, 29). In such
Lamellibranchs as the oysters, scallops and many others which have the
edges of the mantle-skirt quite free, there are numerous tentacles
upon those edges. In _Anodonta_ these pallial tentacles are confined
to a small area surrounding the inferior siphonal notch (fig. 1 [3],
t). When the edges of the mantle ventral to the inhalant orifice are
united, an anterior aperture is left for the protrusion of the foot,
and thus there are three pallial apertures altogether, and species in
this condition are called "Tripora." This is the usual condition in
the Eulamellibranchia and Septibranchia. When the pedal aperture is
small and far forward there may be a fourth aperture in the region of
the fusion behind the pedal aperture. This occurs in _Solen_, and such
forms are called "Quadrifora."

The centro-dorsal point a of the animal of _Anodonta_ (fig. 1 [1]) is
called the umbonal area; the great anterior muscular surface h is that
of the anterior adductor muscle, the posterior similar surface i is
that of the posterior adductor muscle; the long line of attachment u
is the simple "pallial muscle,"--a thickened ridge which is seen to
run parallel to the margin of the mantle-skirt in this Lamellibranch.
In siphonate forms the pallial muscle is not simple, but is indented
posteriorly by a sinus formed by the muscles which retract the
siphons.

It is the approximate equality in the size of the anterior and
posterior adductor muscles which led to the name Isomya for the group
to which _Anodonta_ belongs. The hinder adductor muscle is always
large in Lamellibranchs, but the anterior adductor may be very small
(Heteromya), or absent altogether (Monomya). The anterior adductor
muscle is in front of the mouth and alimentary tract altogether, and
must be regarded as a special and peculiar development of the median
anterior part of the mantle-flap. The posterior adductor is ventral
and anterior to the anus. The former classification based on these
differences in the adductor muscles is now abandoned, having proved to
be an unnatural one. A single family may include isomyarian,
anisomyarian and monomyarian forms, and the latter in development pass
through stages in which they resemble the first two. In fact all
Lamellibranchs begin with a condition in which there is only one
adductor, and that not the posterior but the anterior. This is called
the protomonomyarian stage. Then the posterior adductor develops, and
becomes equal to the anterior, and finally in some cases the anterior
becomes smaller or disappears. The single adductor muscle of the
Monomya is separated by a difference of fibre into two portions, but
neither of these can be regarded as possibly representing the anterior
adductor of the other Lamellibranchs. One of these portions is more
ligamentous and serves to keep the two shells constantly attached to
one another, whilst the more fleshy portion serves to close the shell
rapidly when it has been gaping.

In removing the valves of the shell from an _Anodonta_, it is
necessary not only to cut through the muscular attachments of the
body-wall to the shell but to sever also a strong elastic ligament, or
spring resembling india-rubber, joining the two shells about the
umbonal area. The shell of _Anodonta_ does not present these parts in
the most strongly marked condition, and accordingly our figures (figs.
2, 3, 4) represent the valves of the sinupalliate genus _Cytherea_.
The corresponding parts are recognizable in _Anodonta_. Referring to
the figures (2, 3) for an explanation of terms applicable to the parts
of the valve and the markings on its inner surface--corresponding to
the muscular areas already noted on the surface of the animal's
body--we must specially note here the position of that denticulated
thickening of the dorsal margin of the valve which is called the hinge
(fig. 4). By this hinge one valve is closely fitted to the other.
Below this hinge each shell becomes concave, above it each shell rises
a little to form the umbo, and it is into this ridge-like upgrowth of
each valve that the elastic ligament or spring is fixed (fig. 4). As
shown in the diagram (fig. 5) representing a transverse section of the
two valves of a Lamellibranch, the two shells form a double lever, of
which the toothed-hinge is the fulcrum. The adductor muscles placed in
the concavity of the shells act upon the long arms of the lever at a
mechanical advantage; their contraction keeps the shells shut, and
stretches the ligament or spring h. On the other hand, the ligament h
acts upon the short arm formed by the umbonal ridge of the shells;
whenever the adductors relax, the elastic substance of the ligament
contracts, and the shells gape. It is on this account that the valves
of a dead Lamellibranch always gape; the elastic ligament is no longer
counteracted by the effort of the adductors. The state of closure of
the valves of the shell is not, therefore, one of rest; when it is at
rest--that is, when there is no muscular effort--the valves of a
Lamellibranch are slightly gaping, and are closed by the action of the
adductors when the animal is disturbed. The ligament is simple in
_Anodonta_; in many Lamellibranchs it is separated into two layers, an
outer and an inner (thicker and denser). That the condition of gaping
of the shell-valves is essential to the life of the Lamellibranch
appears from the fact that food to nourish it, water to aerate its
blood, and spermatozoa to fertilize its eggs, are all introduced into
this gaping chamber by currents of water, set going by the
highly-developed ctenidia. The current of water enters into the
sub-pallial space at the spot marked e in fig. 1 (1), and, after
passing as far forward as the mouth w in fig. 1 (5), takes an outward
course and leaves the sub-pallial space by the upper notch d. These
notches are known in _Anodonta_ as the afferent and efferent siphonal
notches respectively, and correspond to the long tube-like afferent
inferior and efferent superior "siphons" formed by the mantle in many
other Lamellibranchs (fig. 8).

Whilst the valves of the shell are equal in _Anodonta_ we find in many
Lamellibranchs (_Ostraea_, _Chama_, _Corbula_, &c.) one valve larger,
and the other smaller and sometimes flat, whilst the larger shell may
be fixed to rock or to stones (_Ostraea_, &c.). A further variation
consists in the development of additional shelly plates upon the
dorsal line between the two large valves (_Pholadidae_). In _Pholas
dactylus_ we find a pair of umbonal plates, a dors-umbonal plate and a
dorsal plate. It is to be remembered that the whole of the cuticular
hard product produced on the dorsal surface and on the mantle-flaps is
to be regarded as the "shell," of which a median band-like area, the
ligament, usually remains uncalcified, so as to result in the
production of two valves united by the elastic ligament. But the
shelly substance does not always in boring forms adhere to this form
after its first growth. In _Aspergillum_ the whole of the tubular
mantle area secretes a continuous shelly tube, although in the young
condition two valves were present. These are seen (fig. 7) set in the
firm substance of the adult tubular shell, which has even replaced the
ligament, so that the tube is complete. In _Teredo_ a similar tube is
formed as the animal elongates (boring in wood), the original
shell-valves not adhering to it but remaining movable and provided
with a special muscular apparatus in place of a ligament. In the shell
of Lamellibranchs three distinct layers can be distinguished: an
external chitinous, non-calcified layer, the periostracum; a middle
layer composed of calcareous prisms perpendicular to the surface, the
prismatic layer; and an internal layer composed of laminae parallel to
the surface, the nacreous layer. The last is secreted by the whole
surface of the mantle except the border, and additions to its
thickness continue to be made through life. The periostracum is
produced by the extreme edge of the mantle border, the prismatic layer
by the part of the border within the edge. These two layers,
therefore, when once formed cannot increase in thickness; as the
mantle grows in extent its border passes beyond the formed parts of
the two outer layers, and the latter are covered internally by a
deposit of nacreous matter. Special deposits of the nacreous matter
around foreign bodies form pearls, the foreign nucleus being usually
of parasitic origin (see PEARL).

Let us now examine the organs which lie beneath the mantle-skirt of
_Anodonta_, and are bathed by the current of water which circulates
through it. This can be done by lifting up and throwing back the left
half of the mantle-skirt as is represented in fig. 1 (3). We thus
expose the plough-like foot (f), the two left labial tentacles, and
the two left gill-plates or left ctenidium. In fig. 1 (5), one of the
labial tentacles n is also thrown back to show the mouth w, and the
two left gill-plates are reflected to show the gill-plates of the
right side (rr, rq) projecting behind the foot, the inner or median
plate of each side being united by concrescence to its fellow of the
opposite side along a continuous line (aa). The left inner gill-plate
is also snipped to show the subjacent orifices of the left renal organ
x, and of the genital gland (testis or ovary) y. The foot thus exposed
in _Anodonta_ is a simple muscular tongue-like organ. It can be
protruded between the flaps of the mantle (fig. 1 [1] [2]) so as to
issue from the shell, and by its action the _Anodonta_ can slowly
crawl or burrow in soft mud or sand. Other Lamellibranchs may have a
larger foot relatively than has _Anodonta_. In _Arca_ it has a
sole-like surface. In _Arca_ too and many others it carries a
byssus-forming gland and a byssus-cementing gland. In the cockles, in
_Cardium_ and in _Trigonia_, it is capable of a sudden stroke, which
causes the animal to jump when out of the water, in the latter genus
to a height of four feet. In _Mytilus_ the foot is reduced to little
more than a tubercle carrying the apertures of these glands. In the
oyster it is absent altogether.

The labial tentacles or palps of _Anodonta_ (n, o in fig. 1 [3], [5])
are highly vascular flat processes richly supplied with nerves. The
left anterior tentacle (seen in the figure) is joined at its base in
front of the mouth (w) to the right anterior tentacle, and similarly
the left (o) and right posterior tentacles are joined behind the
mouth. Those of _Arca_ (i, k in fig. 9) show this relation to the
mouth (a). These organs are characteristic of all Lamellibranchs; they
do not vary except in size, being sometimes drawn out to streamer-like
dimensions. Their appearance and position suggest that they are in
some way related morphologically to the gill-plates, the anterior
labial tentacle being a continuation of the outer gill-plate, and the
posterior a continuation of the inner gill-plate. There is no
embryological evidence to support this suggested connexion, and, as
will appear immediately, the history of the gill-plates in various
forms of Lamellibranchs does not directly favour it. The palps are
really derived from part of the velar area of the larva.

a, Mouth.
b, Anus.
c, Free spirally turned extremity of the gill-axis or ctenidial axis
of the right side.
d, Do. of the left side.
e, f, Anterior portions of these axes fused by concrescence to the
wall of the body.
g, Anterior adductor muscle.
h, Posterior adductor.
i, Anterior labial tentacle.
k, Posterior labial tentacle.
l, Base line of the foot.
m, Sole of the foot.
n, Callosity.]