when it is observed that the finer breed is more profitable The sheep are of a very inferior kind, long in the leg, with coarse wool and hanging ears. A few good Leicesters and improved Cotswold sheep have been introduced, and will probably improve the native breed. The fleece of a very fine ram imported from England being sorted and combed was exhibited in 1885 at Brussells at the annual exhibition of the industrious products of the country, and excited universal admiration for the length and fineness of the staple, and especially for the quantity of the wool. The whole fleece when shorn weighed twenty pounds, and of this nine pounds of fine long dressed wool was obtained. The Belgian pigs are similar to the French, and nearer to the shape of greyhounds than of pigs, with long sharp snouts, and very long legs, the whole body being in the form of an arch of a circle, and very thin. A better breed has however been introduced, and, from the naturally prolific nature of the animal, will soon spread and supersede the old breed. There is a general spirit of agricultural improvement amongst landed proprietors in the country which the government is anxious to encourage. The implements of husbandry used in Brabant are few and of the simplest kind. They use the excellent Flemish swing plough, which they call a foot plough, as it is also called in some parts of England, in contradistinction to a wheel plough. At the same time they also retain the old and heavy turn wrest plough, with a shifting coulter and mould board, as may be still seen in Kent and Sussex; yet they allow that the light Flemish plough does the work as well in the stiffest soils, and requires less force. It is surprising that two instruments so very opposed to each other in principle should be used on the same farm and in the same kind of soil, but the turn wrest plough is the indigenous instrument, and requires less skill in the ploughman: the Flemish plough is of later introduction, and the prejudices against anything new are not yet totally overcome. The plough is universally drawn by horses two abreast, driven in reins. Very few ox teams are seen. The land, in general, is not so neatly tilled as in Flanders, Scotland, or the best agricultural counties in England. There is not the same attention to the straightness and equality of the furrows in ploughing. The harrows are triangular, with wooden tines set at an angle of 45°, which may scratch the surface but cannot penetrate to any depth. A heavy iron drag to tear up the clods, and bring deeply-lying roots to the surface is much wanted, but is not in use any where, as far as we could observe in a tour through this province. A stone roller is used, set in a triangular frame, which drags on the ground, and serves to break the clods, and is a simple useful instrument, of which we annex a figure. The triangle A B C A B ciano was, in the middle ages, an important fef of the Orsini family, who sold it afterwards to the Odesca chi, of whom the estate, with the ducal title attached to it, was purchased a few years since by the banker Torlonia for the sum of 2,200,000 francs. The banks of the lake of Bracciano are well cultivated, and planted with vines and other fruit trees: there are several little towns in its neighbourhood, such as Anguillara, Oriolo, Manziana, &c. The lake is not very deep, and it abounds with fish and fine eels. (Tournon, Etudes Statistiques sur Rome.) BRACCIOLINI, PO'GGIO, son of Guccio Bracciolini, a notary, was born in 1380, at Terranuova, in the Florentine territory. He studied Latin at Florence, under Giovanni da Ravenna, a disciple of Petrarch; and afterwards Greek under Chrysoloras, a learned Byzantine emigrant. About 1402 Poggio went to Rome, where Boniface IX. employed him in the pontifical chancellery, as apostolic secretary or writer of the papal letters. Boniface having died in October, 1404, his successor Innocent VII., continued Poggio in his office, which he held for about half a century under eight successive Popes. Poggio availed himself of the favour of Innocent to obtain an employment in the apostolic chancellery for his friend and school-fellow Leonardo Bruni, of Arezzo. The friendship between these two distinguished scholars continued till death. Innocent having died in 1406, was succeeded by Gregory XII., who was soon after deposed by the Council of Pisa, and replaced by Alexander V. This was the period of the great Western sehism. [BENEDICT, ANTIPOPE.] In the midst of these distractions Poggio withdrew to Florence, where he pursued his literary studies, and found a patron in Niccolò Nicoli, a wealthy Florentine, noted for his love of learning and his encouragement of the learned. When John XXIII. was elected Pope, Poggio returned to his duties of pontifical secretary, and as such he accompanied the Pope to the Council of Constance in 1414. At Constance he applied himself to the study of Hebrew. and in his excursions into the adjoining countries he visited the Abbey of St. Gall, and other monasteries, where he had the good fortune to discover the MSS. of several classical works, which were considered as lost, or of which only imperfect copies existed. He complains, as Boccaceio had done before him, of the monks taking no care of the literary treasures which they possessed, and allowing the valuable MSS. to rotin cellars and dungeons unfit even for con demned criminals. The monastic orders had long since greatly degenerated from their industrious and praiseworthy predecessors of the earlier centuries. Poggio found, among other MSS., copies of Quintilian's Institutions, of Vegetius, Silius Italicus, Ammianus Marcellinus, Columella, Asconius Pedianus's Commentaries upon some of Cicero's Orations, the Argonauties of Valerius Flaccus, several Comedies of Plautus, &c. Continuing his researches after his return to Italy, either by himself or through his friends, he found at Monte Casino a copy of Frontinus de Aquæductibus, he procured from Cologne the 15th book of Petronius Arbiter, and from a monastery at Langres several of Cicero's Orations, which had been considered as lost. Poggio either purchased the MSS., or transcribed them, or pointed them out to persons wealthier than himself. He repeatedly complains, in his works, of the want of encouragement from the great, both clerical and lay. His friends, Bart lommeo da Montepulciano and Cinzio, of Rome, assisted him by their own exertions, and Nicoli by his liberality. It is worth observing, as a corrective to the frequent querulousness of literary men, that at no epoch were scholars in greater estimation than in the 15th century in Italy, as is sufficiently proved by the honours and important offices conferred by the princes of that country on Poggio, Leonardo Bruni, Guarino of Verona, Filelfo, Valla, Beccatelli of Palermo, commonly called 'il Panormita,' George of Trebisond, Pontano, Biondo, and others, simply on account of their literary merit. drags on the ground before the roller, and the horse draws by the hook B. A winnowing machine with a fly and sieves is the only additional instrument in general use. BRACCIANO, LAGO DI, a lake in the Roman state, the antient Sabatinus, about 17 m. N.W. of Rome. It is While Poggio was staying at Constance, he witnessed the of a circular form, about 18 m. in circuit, and lies at the trial and execution, by the sentence of that council, of foot of the ridge called Mount Cimino. It is almost en- Jerome of Prague, on the charge of heresy. He gives a tirely surrounded by hills, except to the S., where it borders most vivid account of that deplorable transaction, in a letter on the wide unwholesome plain which slopes down to the to his friend Leonardo Bruni, which has been often quoted sea. To the S.E. the lake has an outlet in the riv. Arrone, by subsequent historians. Poggio was evidently moved by which flows into the sea at Maccarese. On its S.W. bank the constancy and the eloquence of the defence of the the castle of Bracciano rises with its old embattled walls and Bohemian reformer; and his own knowledge of the corruptowers, on a rock projecting into the lake, with the vil. built tions of the Roman church at that time made him, if not at the foot of the castle, and containing about 1500 inh., openly advocate Jerome's cause, at least commiserate his with several iron-works and a paper manufactory. Brac-fate in terms so strong, that his more prudent friend Leonardo wrote to warn him against giving way to his feel- | ngs. Poggio was still, nominally at least, papal secretary at the time. After Martin V. was solemnly acknowledged as legitimate Pope, and the council was dissolved in 1417, Poggio followed the pontiff on his return to Italy, as far as Mantua, where he suddenly left the papal retinue and repaired to England. Whether he left in disgust, or through fear for having expressed his sentiments too freely on church matters, is not clearly ascertained. While in Constance he nad received an invitation from Cardinal Beaufort, Bishop of Winchester. His expectations however from Beaufort's liberality were disappointed; and at length, having received through some friends in Italy an offer to resume his office at Rome, he left England about 1421. Of his remarks during his residence in England there are scattered fragments in his published letters, and still more in the unedited ones. His picture of the manners and habits of the English is not flattering. He says that they were more addicted to the pleasures of the table than to those of learning; and that the few who cultivated literature were more expert in sophisms and controversial quibbles than in real science. Poggio continued in his office during Martin's pontificate, pursuing at the same time his researches after MSS. and antiquities, for which latter object he made excavations at Ostia, and other parts of the Campagna. He also made Latin translations of the first six books of Diodorus Siculus, and of Xenophon's Cyropædia. Eugenius IV. having, in 1431, succeeded Martin V., was soon after obliged by a popular rebellion to remove his court to Florence. Then came the controversies between the Pope and the Council of Basil, which lasted during the rest of Eugenius's pontificate, till his death in 1447. The greater part of this time was spent by Poggio at Florence, or at a country-house he had purchased in the Val d' Arno, some say with the produce of some classical MSS. which he sold. He gives in his letters a description of this residence, which he had adorned with statues and other remains of antiquity, that he had collected in various places. He wrote there several works, among others his 'Discourse on the Unhappiness of Princes," which he dedicated to Thomas of Sarzana, afterwards Pope Nicholas V., and his virulent invectives against Filelfo, who had attacked the character of Poggio's friend Nicoli. In these invectives the most horrible charges are brought against Filelfo, which however must not be taken literally, for it was the practice of Italian scholars in that as well as in the following ages, to abuse one another without any very strict regard to truth. When the two fierce disputants became reconciled, Poggio wrote a sort of disavowal of his former accusations, which is found at the end of the invectives. In 1435 Poggio married Selvaggia, of the family of Buondelmonte, of Florence, a young and handsome lady, with whom he lived happily. While making up his mind to his marriage, he wrote a dialogue on the question,-An seni sit uxor ducenda? From that time Poggio reformed his life, which had been before rather licentious. In 1437 he published a selection of his letters, written in Latin, like all the rest of his works, according to the fashion of that age. His friend Leonardo Bruni dying in 1444, Poggio composed a Funeral Oration to his memory. He wrote also other Funeral Orations,-for Cardinal Zabarella, who died at the Council of Constance; for the Cardinal Santa Croce, a patron of letters; for Lorenzo de' Medici, brother of the great Cosmo; for Cardinal Sant Angelo, who fell in the battle of Varna against the Turks, &c. His friend Nicholas V., being raised to the pontifical throne in 1447, Poggio, who had returned to Rome and resumed the duties of his office, addressed to the new pontiff an eloquent oration, of mixed eulogy and advice on the duties and dangers of his exalted station,-Oratio ad summum Pontificem Nicolaum V. He did not however forget his own interest, for at the end he speaks of himself as a veteran in the papal court, where he had lived for the space of forty years, and certainly with less emolument than might have been justly expected by one who was not entirely destitute of merit or of learning. Nicholas, who was not displeased at Poggio's frankness, made him liberal presents. To this time belongs Poggio's treatise De Varietate Fortunæ, one of his best works, which presents a good view of Italian politics at the beginning of the 15th century, an interesting sketch of the remains of antient Rome in Poggio's time, and a curious account of the travels of the Venetian, Niccolò Conti, in He also wrote Dialogus adversus Hypocrisin, in the east which, as well as in his disquisition, De Avaritia et Luxuria, he inveighs against the vices of the clergy, and especially of the monks, which were certainly very flagrant in that age, and were the main cause that led to the great reformation in the following century. Notwithstanding his satirical freedom he preserved the good graces of Nicholas, in support of whose right to the papacy he wrote a bitter invective against his rival the antipope Felix, in which, as usual with Poggio, his accusations outstripped truth. A violent quarrel with George of Trebisond, about some literary matters, brought the two scholars to blows, and the Greek was in consequence obliged to quit Rome. In 1450, the plague being in Rome, Poggio withdrew to Florence, where he wrote his Facetic, a collection of humorous anecdotes and repartees, some of which are very indecent. He also wrote Historia Disceptativa Convivialis, or discussions upon various philological, historical, and moral subjects; Disputatio de Infelicitate Principum, in which he speaks of princes in a strain of democratic contempt, rather odd in a man who had lived almost all his life at courts; De Nobilitate Dialogus, in which the various meanings of nobility are examined; De Miseria Conditionis Humanæ. In 1453, on the death of Carlo Aretino, chancellor of Florence, Poggio, through the influence of the Medici, was appointed his successor. He finally quitted the Roman court after having been fifty years in its service; and it was not without regret that he parted from his kind patron Pope Nicholas. Having now access to the archives of Florence, he undertook a history of that republic,-Historia Florentinæ, lib. viii., which embraces the period from 1350 to 1455. It was translated into Italian by his son Jacopo, and printed in 1476, and afterwards republished in a more correct and improved form by Serdonati, Florence, 1598. The Latin text was not published till 1715, by Recanati, who prefixed to it a biography of the author. Poggio has been charged with marked partiality for his countrymen in his history. Another deficiency is noted by a grave authority, Machiavelli, who, in the preface to his own history, observes that both Poggio and Leonardo Bruni, two excellent historians, had diligently described the wars between Florence and the other states and princes, but with regard to the civil contentions of the republic, its internal factions and their results, they had been either silent or extremely laconic in their account, either because they fancied them beneath the dignity of history, or perhaps because they were afraid of offending the relatives and descendants of persons who had figured in those transactions.' Poggio died at Florence in 1459, and was buried with great honours in the church of Santa Croce, near his friend Leonardo Bruni. A statue of him by the sculptor Donatello is in the duomo or cathedral. Poggio was one of the most distinguished scholars of the epoch of the revival of literature, and one of those who contributed most to the spreading of that revival. His long life, the offices of trust which he filled, his travels, his extensive correspondence, his multifarious learning, all contribute to render him one of the most remarkable writers of the fifteenth century. His works, especially his Orations and his Epistolæ, are remarkable for their eloquence and fluency of style, though their language does not equal in classic purity that of Poliziano and some other latinists of the following age. His sentiments are noted for their independence and frankness; even in his addresses to the great, his language, though courtly, is free from flattery. He had an ample share of Florentine causticity of humour, and his invectives are virulent and outrageous beyond the limits of all decency and justice; this was however the fault of the generality of his contemporaries. But he could_also be a staunch friend as well as a violent enemy. Even as a monitor he could divest himself of all unbecoming asperity, as he proved by his reproof to Beccatelli, on the occasion of the latter having written an infamous book called the Hermaphrodite, which was burnt in various towns of Italy by the public executioner. While Valla and others charitably wished that the author had shared the fate of his book, Poggio wrote to the Panormita, expressing his regret at seeing such a production from the pen of one capable of better things, reminding him that he was a Christian living among Christians, and not among the worshippers of the heathen gods, and exhorting him to apply himself in future to graver and more becoming studies.' The works of Poggio have never been properly collected. The Basil edition, Poggii Opera, 1538, wants many of them, and is also typographically incorrect. The dialogue 'against Hypocrisy, which was published separately at Lyons in 1679, had appeared before in a collection called Fasciculus rerum expetendarum et fugiendarum, Cologne, 1535. The treatise De Varietate Fortuna' was printed first at Paris, in 1723, with fifty-seven inedited letters. But most of his letters still remain inedited and scattered about different libraries. A great number of them exist in the Riccardiana at Florence, which contain many curious particulars of his life and times. The Advocate Tonelli has made good use of them for his Italian translation of Shepherd's clever Life of Poggio, Florence, 1825. Poggio's funeral oration for Cardinal Zabarella, which he delivered before the council of Constance, in 1417, Iras been published separately, 'Oratio in funere Francisci Zabarellæ, habita in Concilio Constantiensi, anno 1417, Padua, 1655. But most of his other orations remained inedited. He also translated from the Greek, Lucian's 'Dialogue on the Ass,' which is printed in the Basil edition of his works. The miscellany called 'Poggiana,' by Lenfant, 1720, which professes to give an abstract of his life, opinions, &c., is full of errors. Poggio's Facetime' have gone through many editions. Poggio's son Jacopo was a man of learning, but after being in his youth the friend of the Medici, he conspired with the Pazzi against Lorenzo, and being seized after the murder of Giuliano, was publicly hanged in 1478. BRACELET. [ARMILLA.] BRACHE LYTRA (Entomology), according to Mr. Stephens's arrangement of insects, forms the sixth division of the order Coleoptera. M. Latreille, however, places this tribe of insects as the second family of the Pentamerous Coleoptera. The insects of this section (which is by Linnæus called Staphylinus) may be distinguished by the elongate form of the body and the shortness of the wingcases, which in most instances scarcely cover one-third of the length of the abdomen: their maxillæ are furnished with only one palpus. The apex of the abdomen is provided with two vesicles, which can be protruded at the will of the animal. The habits of the Brachelytra are very various, but the greater number of the species are found in putrid animal or vegetable substances, upon which they feed; some are carnivorous. The shortness of the wing-cases probably allows of a greater flexibility in the body. BRA'CHINUS, a genus of coleopterous insects belonging to the section truncatipennes; generic characters-body oblong, head and thorax comparatively narrow, the latter generally somewhat of a truncated heart shape; palpi and antennæ rather thick, the terminal joint of the former is slightly thicker than the basal joints, and has its apex truncated; mentum emarginate, and furnished with a small tooth-like process in the middle. The Brachini possess a remarkable power of violently expelling from the anus a pungent acrid fluid; which, if the species be large, has the power of producing a discoloration of the skin similar to that caused by nitric acid. A loud report, considering the size of the insect, accompanies the expulsion of this fluid, which, being discharged, instantly evaporates. About five species of the genus Brachinus have been found in this country, of which B. crepitans is the most common; it is found under stones, and occurs plentifully in chalky districts. This species is rather less than half an inch long; the head, thorax, and legs are of a yellowish red colour; the wing-cases are greenish, or blue black. The antennæ are reddish, with the third and fourth joints black. Many of the species of Brachinus resemble the above in colour. The species of the genus Aptinus (a genus very closely allied and differing chiefly in being apterous) are generally of a yellow colour, having four black spots on the elytra; the head and thorax are also often more or less suffused with black; they are likewise of a larger size for the most part, and abound more particularly in warm climates. BRA'CHIONUS (Müller), Zoology; a genus of minute animals, found both in stagnant fresh water and in sea water. Their organization has produced some doubt among naturalists as to their proper place in the scale of creation. Lamarck arranged them under his Rotifera (wheel-bearing! animals) being the second section of his Ciliated Polypes, and having one or two ciliated and rotatory organs at the orifice of the mouth. Cuvier placed them in the first order (Rotifera) of his Infusoria, which forms his fifth and last class of the Zoophytes-in short, the class at the extreme end of the animal kingdom. De Blainville also brings them under the Rotifera, which form the first section of his Microzoaria heteropoda. The following is De Blainville's definition of the genus : Body more or less covered by a shell (or sheath), formed of one or two pieces, and more or less prolonged posteriorly by a caudiform abdomen, two tufts of vibratory cilia at the anterior extremity. Savigny, Schweigger, Schrank, Bory de St. Vincent, Carus, have all contributed to throw light upon these microscopic creatures. De Blainville thus writes in his Actinologie' (1834):'In the impossibility under which we find ourselves of characterizing, by the particular disposition of their appendages, the genera, more or less numerous, which may be formed among the Microzoaria, we propose to extend to all the species, whose bodies are covered by a sort of shell of one or two pieces for a more or less considerable part of their extent, the denomination of Brachion, devised by Hill and adopted by Pallas and Lamarck ****. We have already observed many species of this genus belonging to the different sec tions. Brachionus urceolaris of the first section is common in all stagnant fresh waters; it is very probably the Rotifera of Hill, Essay 13, p. 288, concerning which that author gives very interesting details that show it to be a true entomostracous animal. [ENTOMOSTRACA]. 'The Corona of Corti belongs also, without doubt, to this section. 'We have also studied the Trichoda piscis of Müller, which is certainly a Brachion. We cannot conceive how Müller could say that it creeps after the manner of the Planaria, for it attaches itself by the extremity of its tail, and it travels as if it were provided with a great number of appendages under its shell. 'Brachionus ovalis has also been often presented to our observations. It has certainly two tufts of vibratory cilia before, and behind a pair of sufficiently long appendages, by the aid of which it is also able to fix itself. Its shell appeared to us to be bivalve; but of this we are not certain. 'Brachionus patina we have seen once, and observed sufficiently well the particularities pointed out by Müller. It was in the water of one of the basins of the Jardin du Roi, containing an innumerable quantity of Entomostraca. 'Upon the whole, we are very much inclined to think that the Brachions are only the young states of Entomostraca, whose habits for the most part they have.' Ehrenberg, who has distinguished himself by his luminous researches into the organization of the Infusoria in general, and of the rotatory animals in particular, states in his memoir upon them (1834) that he has already discovered in the latter, 1. A system of organs of nutrition, with all their details. 2. A double sexual system, observed in its entire develop ment. De Blainville divides the genus into the following sections: | the physiologist and zootomist; and we select the following 'General Remarks' as the part of the paper most appropriate for insertion here, premising that the generative system of the Brachiopoda is cryptandrous. Species whose univalve shell is oval, much shorter than the body, prolonged posteriorly into a very long caudiform abdomen, which is provided at its termination with a pair of very short appendages. Example. Brachionus urceolaris. (Müller.) Species whose body, entirely covered by a nearly circular shell, is terminated behind by a pair of very long and setaceous appendages. Genus SQUAMELLA of Bory de St. Vincent. Example. Brachionus bractea. (Müller.) BRACHIO'PODA, or BRACHIOPODOUS MOL LUSCA (Zoology), Cuvier's fifth class of Mollusks, the Palliobranchians (Palliobranchiata) of De Blainville, being the first order of the latter's third class of Mollusks (Acephalophora). This class, though comparatively low in the scale of creation, is interesting to the physiologist, and of considerable value to the geologist, who finds in the fossil forms no small portion of those natural medals which indicate the history of the stratification of our globe. We have, therefore, entered more largely into the natural history of the Brachiopoda than their consequence as organized beings would otherwise warrant in a work of this description. 'On comparing together, says Mr. Owen, 'the three genera of Brachiopoda above described, we find that although Orbicula, in the muscular structure of its arms and the proportion of the shell occupied by its viscera, is intermediate to Lingula and Terebratula, yet that in the structure of its respiratory organs its simple alimentary canal, and its mode of attachment to foreign bodies, it has a greater affinity to the latter genus. The modifications that can be traced in the organization of these genera have an evident reference to the different situations which they occupy in the watery element. Lingula, living more commonly near the surface, and sometimes where it would be left exposed by the retreating tide, were it not buried in the sand of the shore, must meet with a greater variety and abundance of animal nutriment than can be found in those abysses in which Terebratula is destined to reside. Hence its powers of prehension are greater, and Cuvier suspects it may enjoy a species of locomotion from the superior length of its pedicle. The organization of its mouth and stomach indicates, however, that it is confined to food of a minute description; but its convoluted intestine shows a capacity for extracting a quantity of nutriment proportioned to its superior activity and the extent of its soft parts. A more complex and obvious respiratory apparatus was therefore indispensable, and it is not surprising that the earlier observers failed to detect a corresponding organization in genera destined to a more limited sphere of action. The respiration indeed, as well as the nutrition of animals living beneath a pressure of from sixty to ninety fathoms of sea water, are subjects of peculiar interest, and prepare the mind to contemplate with less surprise the wonderful complexity exhibited in the minutest parts of these diminutive creatures. In the stillness pervading these abysses they can only maintain existence by exciting a perpetual current around them, in order to dissipate the water already loaded with their effete particles and bring within the reach of their prehensile organs the animalcula adapted for their support. The actions of Terebratula and Orbicula, from the firm attachment of their shells to foreign substances, are thus confined to the movements of their brachial and branchial filaments, and to a slight divarication or sliding motion of their protecting valves; and the simplicity of their digestive apparatus, the corresponding simplicity of their branchia, and the diminished proportion of their soft to their hard parts, are in harmony with such limited powers. The soft parts in both genera are, however, remarkable for the strong and unyielding manner in which they are connected together. The muscular parts are in great proportion and of singular complexity, as compared with ordinary bivalves; and the tendinous and aponeurotic parts are remarkable for the similarity of their texture and appearance to those of the highest classes. By means of all this strength they are enabled to Cuvier, in his anatomy of Lingula anatina, in the Annales du Muséum, first made known that organization, by which the mantle, in addition to its office of secreting the shelly defence of these bivalves, is made subservient to the circulating system. Instead of the branchia of the ordinary bivalves, he found in the situation usually occupied by them two fringed and spirally disposed arms, and that the branchia presented themselves on the internal surface of both lobes of the mantle in oblique parallel lines. He further found that these lobes were traversed by vessels of considerable size, which returned the blood from the organs of respiration, and that these branchial veins terminated in two symmetrical systemic hearts. Here was a new type of circulation, and to the mollusks which presented these in-perform the requisite motions of the valves at the depths in teresting and important modifications he gave the name at the head of our article, significative of the fringed arms which in this class took the place of the foot or organ of progression in the cockle, &c. Lamanon and Walsh had previously taken the analogous parts of Terebratula for branchia, and Pallas, who is not quoted by Cuvier, describes the arms of Terebratula with minuteness and accuracy, but considers them as branchiæ, and compares them to those of a fish. De Blainville, in the Dictionnaire des Sciences Naturelles,' gives an account of the organization of Terebratula. But both Cuvier and De Blainville were led into error in their attempts to trace out some parts of the organization of Terebratula; and it was reserved for Mr. Owen, in his acute, accurate, and interesting paper, 'On the Anatomy of the Brachiopoda of Cuvier, and more especially of the Genera Terebratula and Orbicula, published in the Transactions of the Zoological Society of London,* and derived from the dissection of specimens brought to this country by Mr. Cuming and Captain James Ross, R. N., fully to investigate the subject so as to leave little or nothing to be desired upon the subject of the anatomy of Lingula and of the two genera last named. Our limits will not permit us to follow the learned author through his memoir, the whole of which, together with the beautiful illustrations that accompany it, is worthy of the most attentive perusal by ́☀ Vol, i. p. 145, which they are met with. Terebratula, which is more remarkable for its habitat, has an internal skeleton superadded to its outward defence, by means of which, additional support is afforded to the shell, a stronger defence to the viscera, and a more fixed point of attachment to the brachial cirri. The spiral disposition of the arms is common to the whole of the brachiopodous genera whose organization has hitherto been examined; and it is therefore probable that in that disposed, and that the internal calcareous spiral appendages remarkable genus Spirifer the entire brachia were similarly psittacea had been so obtained, this species would have were their supports. If, indeed, the brachia of Terebratula presented in a fossil state an internal structure very similar to that of Spirifer. In considering the affinities of the Brachiopoda to the other orders of Mollusca, I shall compare them, in the first place, with the Lamellibranchiate bivalves, to which they present the most obvious relations in the nature and forms of their organs of defence. To these they are in some respects superior. The labial arms are more complex prehensile organs than the corresponding vascular lamine on either side the mouth of the Lamellibranchiata. The whole muscular system is more complex; and the opening as wen action, indicates a higher degree of organization than where as the closing of the shell being regulated by muscular the antagonizing power results from a property of the cardinal ligament, which is independent of vitality, viz, elas ticity. With respect, however, to the respiratory organs, less distance towards the opposite margin of the valve; the the modifications which these have presented in Orbicula loop then suddenly turns towards the perforate valve, and is and Terebratula show the Brachiopods to be still more in- bent back upon itself for a greater or less extent in different ferior to the Lamellibranchiata than was to be inferred from species. When the loop is very short and narrow, as in Ter. the structure of the branchia in Lingula; and notwith- vitrea, Brug., there is but a small tendency towards a restanding the division of the systemic heart, I consider that flected portion; but where the loop is of great length and there is also an inferiority in the vascular system. Each width, as in Ter. Chilensis, Brod., Ter, dorsata, Lam., and heart, for example, in the Brachiopoda is as simple as in Ter. Sowerbii, King., the reflected portion is considerable. Ascidia, consisting of a single elongated cavity, and not The loop, besides being fixed by its origins or crura, is comcomposed of a distinct auricle and ventricle, as in the ordi- monly attached to two processes going off at right angles nary bivalves; for in these, even when, as in the genus from the sides, or formed by a bifurcation of the extremity, Arca, the ventricles are double, the auricles are also dis- of a central process, which is continued forwards to a greater tinctly two in number; and in the other genera, where the or less extent from the hinge; but it is sometimes entirely ventricle is single, it is mostly supplied by a double auricle. free, except at its origins, as, e. g., in Ter. vitrea. This reThe two hearts of the Brachiopoda, which in structure re-flected loop, forming two arches on either side the mesial semble the two auricles in the above bivalves, form therefore plane, towards which their concavities are directed, I have a complexity or superiority of organization more apparent figured as it exists in Ter. Chilensis and Ter. Sowerbii. It than real. Having been thus led to consider the circulating is represented of a similarly perfect form in Ter. dentata, by as well as respiratory systems as constructed on an inferior M. de Blainville in his Malacologie; and the same appaplan to that which pervades the same important systems in ratus in Ter, dorsata is very well figured by Chemnitz; by the Lamellibranchiate bivalves, I infer that the position of Sowerby, and more recently by G. Fischer de Waldheim. the Brachiopoda in the natural system is inferior to that A similar form is also figured in another species of Tereorder of Acephala. bratula by Poli, 'Among the relations of the Brachiopoda to the Tunicated Acephala, and more especially to the Asoidiæ, we may first notice an almost similar position of the extended respiratory membranes in relation to the mouth, so that the currents containing the nutrient molecules must first traverse the vascular surface of that membrane before reaching the mouth; the simple condition, also, to which the branchiæ are reduced in Orbicula and Terebratula indicates their close affinity to the Ascidia, But in consequence of the form of the respiratory membranes in the Brachiopoda, which is so opposite to that of the sacciform branchia of the Ascidia, the digestive system derives no assistance from that part as a receptacle for the food, and the superaddition of prehensile organs about the mouth became a necessary consequence. The Brachiopods again are stationary, like the Ascidia, and resemble the Boltenia in the pedunculated mode of their attachment to foreign bodies, With the Cirripeds their relation is one of very remote analogy; their generative, nervous, and respiratory organs being constructed on a different type, and their brachia manifesting no trace of their articulate structure. In all essential points the Brachiopoda closely correspond with the Acephalous Mollusca, and we consider them as being intermediate to the Lamellibranchiate and Tunicate orders; not however possessing, so far as they are at present known, distinctive character of sufficient importance to justify their being regarded as a distinct class of Mollusks, but forming a separate group of equal value with the Lamellibranchiata. The following is De Blainville's arrangement, slightly modified: Shell Symmetrical. Genus TEREBRATULA (Bruguières). Animal depressed, circular or oval, more or less elongated. Shell delicate, equilateral, subtriangular, inequivalve, one of the valves larger and more rounded (bombée) than the other, prolonged backwards into a sort of heel, which is sometimes recurved into a kind of hook-like process and pierced at its extremity by a round hole, but more frequently divided into a fissure more or less large and of variable form. The opposite valve generally smaller, flatter, and sometimes operculiform. Of that complicated loop or internal support to which the arms are attached we shall presently speak at large. Hinge on the border, condyloid, placed on a straight line, and formed by the two oblique articulating surfaces of the one valve placed between the corresponding projections of the other. A sort of tendinous ligament comes forth from the hole or fissure above described, by which the animal fizes itself to submarine bodies. The following is Mr. Owen's description of the peculiar, complex, and extremely delicate testaceous apparatus, sometimes called the carriage-spring' by collectors, attached to the internal surface of the imperforate valve: "The principal part of this internal skeleton, as it may ne termed, consists of a slender, flattened, calcareous loop, the extremities of which are attached to the lateral elevated ridges of the hinge; the crura of the loop diverge, but again approximate to each other as they advance for a greater or The arches of the loop are so slender, that, notwithstanding their calcareous nature, they possess a slight degree of elasticity and yield a little to pressure; but, for the same reason, they readily break if the experiment be not made with due caution, The interspace between the two folds of the calcareous loop is filled up by a strong but extensile membrane, which binds them together, and forms a protecting wall to the viscera: the space between the bifurcated process in Ter, Chilensis is also similarly occupied by a strong aponeurosis. In this species the muscular stem of each arm is attached to the outer sides of the loop and the intervening membrane, They commence at the pointed processes at the origins of the loop, advance along the lower portion, turn round upon the upper one, and are continued along it till they reach the transverse connecting bar, where they advance again forwards and terminate by making a half spiral twist in front of the mouth. It is these free extremities which form the third arm mentioned by Cuvier. These arms are ciliate on their outer side for their entire length, but the cilia are longer and much finer than the brachial fringes of Lingula; and except at the extreme ends, which have a slight incurvation, they are uniformly straight. There is thus an important difference between Lingula and those species of Terebratula which resemble Ter. Chilensis in the powers of motion with which the arms are endowed; since from their attachment to the calcareous loop they are fixed, and cannot be unfolded outwards as in Lingula. Owing to this mode of connexion, and their ciliated structure, their true nature was much more liable to be mistaken by the early observers, though it appears not to have escaped the discrimination of Linnæus, who, as Cuvier has observed, founded his character of the animal of Anomia on the organization of one of the Terebratula which he included in that genus." The recent species are numerous and widely diffused, and the genus appears to be capable of flourishing in extremely warm and extremely cold regions, as well as in more temperate climates. Thus some of the species have been found in the Indian seas and at Java (Ter. flavescens, Lam., for example), and Ter, psittacea, brought home from the late expedition by Captain James Ross, R. N., was fished up from a depth of twenty-two fathoms near Felix Harbour, in lat. 70° N. on the E. side of Boothia. The average depth at which Terebratula has been found ranges from ten to ninety fathoms. De Blainville has thus subdivided the species: A. Summit of the larger valve pierced with a round hole, well defined. 1. Valves triangular, with a straight anterior border Example. Terebratula digona (fossil), U Terebratula digono, ] |