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Aristotle (book viii. c. 28) writes of Libyan serpents of enormous size, and relates, that certain voyagers to that coast were pursued by some of them so large that they overset one of the triremes. The two monstrous snakes (aivà réλwpa) sent by Juno to strangle the infant Hercules in his cradle, described by Theocritus in his 24th Idyll, exhibit some of the peculiarities of these reptiles. The way in which Theocritus represents them to have rolled their folds around the boy, and relaxed them when dying in his grasp, indicates the habit of a constricting serpent*. Virgil's Laocoon, and the unrivalled marble group, which the poet's description most probably called into existence, owe their origin undoubtedly to the stories current of constricting serpents. Valerius Maximus (book i. c. 8, s. 19), quoting Livy, gives a relation of the alarm into which the Romans under Regulus were thrown by an enormous snake, which had its lair on the banks of the Bagradas, or Magradas (Mejerda), near Utica. It is said to have swallowed many of the soldiers, to have killed others in its folds, and to have kept the army from the river; till at length, being invulnerable by ordinary weapons, it was destroyed by heavy stones slung from the military engines used in sieges. But, according to the historian, its persecution of the army did not cease with its death; for the waters were polluted with its gore, and the air with the steams from its corrupted carcase, to such a degree, that the Romans were obliged to move their camp, taking with them however the skin, one hundred and twenty feet in length, which was sent to Rome +. Gellius, Orosius, Fiorus, Silius Italicus, and Zonaras, make mention of the same serpent nearly to the same effect. Pliny (viii. 14, De Serpentibus Maximis et Bois) says, that Megasthenes writes that serpents grow to such a size in India, that they swallowed entire stags and bulls. (See also Nearchus, quoted by Arrian. Indic. 15.) He speaks too of the Bagradian serpent above-mentioned as matter of no- The Box more especially so called, have a spur on each toriety, observing that it was one hundred and twenty feet side of the vent, the body compressed, largest in the middle, long, and that its skin and jaws were preserved in a temple the tail prehensile, and small scales on the posterior part at Rome till the time of the Numantine war: and he adds, of the head. Among them are found the largest of serpents. that the serpents called Boæ in Italy confirm this, for that Some of the species attain thirty or forty feet in length, and they grow to such a size, that in the belly of one killed on the become capable of swallowing dogs, deer, and even oxen, Vatican hill in the reign of Claudius an entire infant was according to travellers, after having crushed them in their found. Suetonius (in Octav. 43) mentions the exhibition folds, lubricated them with their saliva, and enormously diof a serpent, fifty cubits in length, in front of the comitium.lated their jaws and throat: this operation is a very long one. But, without multiplying instances from Ælian and others, we will now come to more modern accounts. Bontius (v. 23) says, 'The Indian serpents are so multitudinous, that my paper would fail me before I enumerated them all; nevertheless, I must say something about the great ones, which sometimes exceed thirty-six feet in length, and are of such capacity of throat and stomach that they swallow entire boars. He then speaks of the great power of distention in the jaws, adding, To confirm this, there are those alive who partook with General Peter Both of a recently swallowed hog, cut out of the belly of a serpent of this kind. They are not venomous, but they strangle by powerfully applying their folds around the body of a man or other animal.' Mr. M'Leod, in his interesting Voyage of H. M. S. Alceste,' p. 312, gives the following account:

always victorious. A negro herdsman belonging to Mr. Abson (who afterwards limped for many years about the fort) had been seized by one of these monsters by the thigh; but from his situation in a wood, the serpent, in attempting to throw himself around him, got entangled with a tree; and the man, being thus preserved from a state of compression, which would instantly have rendered him quite powerless, had presence of mind enough to cut with a large knife, which he carried about with him, deep gashes in the neck and throat of his antagonist, thereby killing him, and disengaging himself from his frightful situation. He never afterwards, however, recovered the use of that limb, which had sustained considerable injury from his fangs and the mere force of his jaws. All these gigantic serpents were, most probably, the Pythons of modern nomenclature. According to Pliny, the name Boa was given to these serpents because they were said to be at first nourished by the milk of cows; and Jonston and others observe, that they derived the name not so much from their power of swallowing oxen, as from a story current in old times of their following the herds and sucking their udders. Boa is also stated by some to be the Brazilian name for a serpent. Among modern systematic writers, Linnæus may be considered as the first establisher of the genus. Laurenti, Boddaert, Daubenton, Schneider, Lacépède, Latreille, and others adopted it, in many instances with alterations and corrections. At one time the genus comprehended all serpents, venomous or not, the under part of whose body and tail were furnished with scaly transverse bands, or scuta, formed of one piece only, and which had neither spur nor rattle at the end of the tail. After the venomous serpents were separated from them, they were found sufficiently numerous and were again subdivided.

It may here be mentioned, that during a captivity of some months at Whidah, in the kingdom of Dahomey, on the coast of Africa, the author of this narrative had opportunities of observing snakes more than double the size of this one just described §; but he cannot venture to say whether or not they were of the same species, though he has no doubt of their being of the genus Boa. They killed their prey, however, precisely in a similar manner; and, from their superior bulk, were capable of swallowing animals much larger than goats or sheep. Governor Abson, who had for thirty-seven years resided at Fort William (one of the African Company's settlements there), described some desperate struggles which he had either seen, or had come to his knowledge, between the snakes and wild beasts, as well as the smaller cattle, in which the former were The exquisite beauty of the Idyll can only be equalled by the grandeur of design and execution displayed by Reynolds in his picture,

The passage cited by Valerius from Livy must have been in the lost de cade (the 2nd). The reader will find however the story recorded in the supplement to Livy (xviii. 15).

Jonston, after quoting this passage, adds, that it is probable that the Boa grows to this size in Calabria, for that Cuccinus, bishop of St. Angelo, writes to Thomasinus, that one which had devoured the flocks and herds was killed, in a field near the town and within his diocese, by a shepherd, and that the mandibles, two palms in length, were to be seen in the church of the Virgin. (Deiparæ de Urseolo.)

See Post, p. 23,

The following is Cuvier's definition of a true Boa in modern nomenclature:

A remarkable part of their anatomy is, that their smaller lung is only one half shorter than the other.

Before we enter upon the subdivision of this family, we will examine some of the most remarkable points in the structure and organization of the serpent, admirably adapted to its habits.

On looking at this representation of the skeleton of a boa constrictor, drawn from the beautiful preparation in the British Museum, we first observe the strong close-set teeth, of which there is a double row on each side of the upper jaw, all pointing backwards, and giving the serpent the firmest hold of its struggling victim, which is thus deprived of the power of withdrawing itself when once locked within the deadly jaws. Serpents do not masticate. The prey is swallowed whole; and to assist deglutition, their under jaw consists of two bones easily separable at the symphysis, or point of junction, while the bone similar to the os quadratum in birds, by the intervention of which it is fitted to the cranium, further facilitates the act. The upper jaw moreover is so constructed as to admit of considerable motion.

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We next observe the spine, formed for the most extensive mobility, and the multitude of ribs constructed as organs of rapid progression, when joined to the belly scales, or scuta, with which the whole inferior surface of the body may be said to be shod. When the snake,' writes Sir Everard Home, begins to put itself in motion, the ribs of the opposite sides are drawn apart from each other, and the small cartilages at the end of them are bent upon the upper surfaces of the abdominal scuta, on which the ends of the ribs rest; and, as the ribs move in pairs, the scutum under each pair is carried along with it. This scutum by its point from whence to set out anew. posterior edge lays hold of the ground, and becomes a fixed This motion is beautifully seen when a snake is climbing over an angle to get upon a flat surface. When the animal is moving, it alters its shape from a circular or oval form to something ap proaching to a triangle, of which the surface on the ground forms the base. The coluber and boa having large abdominal scuta, which may be considered as hoofs or shoes, arg

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[Skeleton of boa constrictor.]

the best fitted for this kind of progressive motion.' (Lectures | to the next muscle, and is inserted into the third rib behind on Comparative Anatomy, vol. i.)

Sir Everard, in the same lecture, speaking of the ribs as organs of locomotion, says An observation of Sir Joseph Banks during the exhibition of a coluber of unusual size first led to this discovery. While it was moving briskly along the carpet, he said he thought he saw the ribs come forward in succession, like the feet of a caterpillar. This remark led me to examine the animal's motion with more accuracy, and on putting the hand under its belly, while the snake was in the act of passing over the palm, the ends of the ribs were distinctly felt pressing upon the surface in regular succession, so as to leave no doubt of the ribs forming so many pairs of levers, by which the animal moves its body from place to place.

It is not intended to detract in the least from the masterly descriptions given in the lecture here quoted; but it is due to the sharp-sighted Tyson to observe, that the locomotive power of the ribs was detected and published by him in his excellent observations on the anatomy of the rattle-snake. (See Phil. Trans.)

Sir Everard Home informs us by what additional mechanism this faculty is effected. The ribs, he observes, are not articulated in snakes between the vertebræ, but each vertebra has a rib attached to it by two slightly concave surfaces, that move upon a convex protuberance on the side of the vertebra, by which means the extent of motion is unusually great, and the lower end of each vertebra having a globular form fitted to a concavity in the upper end of the vertebra below it, they move readily on one another in all directions. The muscles which bring the ribs forward, according to Sir Everard, consist of five sets, one from the transverse process of each vertebra to the rib immediately behind it, which rib is attached to the next vertebra. The next set goes from the rib a little way from the spine, just beyond where the former terminates, it passes over two ribs, sending a slip to each, and is inserted into the third; there is a slip also connecting it with the next muscle in succession. Under this is the third set, which arises from the posterior side of each rib, passes over two ribs, sending a lateral slip

it. The fourth set passes from one rib over the next, and is inserted into the second rib. The fifth set goes from rib to rib. On the inside of the chest there is a strong set of muscles attached to the anterior surface of each vertebra, and passing obliquely forwards over four ribs to be inserted into the fifth, nearly at the middle part between the two extremities. From this part of each rib a strong flat muscle comes forward on each side before the viscera, forming the abdominal muscles, and uniting in a beautiful middle tendon, so that the lower half of each rib, which is beyond the origin of this muscle, and which is only laterally connected to it by loose cellular membrane, is external to the belly of the animal, and is used for the purpose of progressive motion; while that half of each rib next the spine, as far as the lungs extend, is employed in respiration. At the termination of each rib is a small cartilage, in shape corresponding to the rib, only tapering to the point. Those of the opposite ribs have no connexion, and when the ribs are drawn outwards by the muscles, they are separated to some distance, and rest through their whole length on the inner surface of the abdominal scuta, to which they are connected by a set of short muscles; they have also a connexion with the cartilages of the neighbouring ribs by a set of short straight muscles. These observations apply to snakes in general; but the muscles have been examined in a boa constrictor, three feet nine inches long, preserved in the Hunterian Museum. In all snakes, adds the author, the ribs are continued to the anus, but the lungs seldom occupy more than one half of the extent of the cavity covered by the ribs. Consequently these lower ribs can only be employed for the purpose of progressive motion, and therefore correspond in that respect with the ribs in the Draco volans superadded to form the wings. [See DRAGON.]

The subjoined cut, copied from that given as an illustration by Sir Everard Home, will explain the articulating surfaces of the vertebrae and ribs; and on the under surface of the former will be seen the protuberance for the attachment of the muscles which are employed in crushing the animals round which the snake entwines itself,

or spurs, he proceeds to his own observations made on Boa Constrictor, Scytale, and Cenchris. He says, that the spur or nail on each side of the vent in the boa constrictor and other species of the genus is a true nail, in the cavity of which is a little demi-cartilaginous bone, or ungual phalanx, articulated with another bone much stronger which is concealed under the skin. This second bone of the rudiment of a foot in the Boa has an external thick condyle, with which the ungual phalanx is articulated, as above stated: it presents, besides, a smaller internal apophysis, which places it in connexion with the other bones of the skeleton. These bones are the appendages of a tibia or leg bone, the form and relative position of which will be understood by a reference to the subjoined cuts, copied from Dr. Mayer's 'Memoir.'

The figure above given represents the tail of a boa constrictor: a, the vent; b, the hook or spur of the left side; The cut exhibits two vertebrae, and portions of two ribs of c, the subcutaneous muscle; d, ribs and intercostal muscles; a so-called boa constrictor, drawn with his usual accurate, transverse muscle of the abdomen; f, bone of the leg enfidelity and skill by W. Clift, Esq., from a skeleton sent veloped in its muscles; g, abductor muscle of the foot; from the East Indies by the late Sir William Jones, and h, adductor muscle of the foot. The arrangement of the deposited in the Hunterian Museum. The letters a, a point teristic of the true boas, will be here observed. In the pyscuta, or shields, of one entire piece under the tail, characto the protuberance on the under surface for the attach-thons the shields beneath the tail are ranged in pairs. ment of the constricting muscles, according to Sir Everard Home.

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Though the term boa constrictor is used throughout by Sir Everard Home in his lecture, there can be little doubt that the serpent sent from India by Sir William Jones was a python. The small specimen from which the description of the organs employed in progressive motion was taken may have been a boa. But whether boa or python, it would have had the hooks or spurs near the vent, and the bones and muscles belonging to these spurs, which are of no small consequence in the organization of a boa or a python, rudiments of limbs though they be; these appear to have escaped Sir Everard Home's observation, occupied as he was in following out the mechanism of progressive motion.

No one can read of the habits of these reptiles in a state of nature without perceiving the advantage which they gain when, holding on by their tails on a tree, their heads and bodies in ambush, and half floating on some sedgy river, they surprise the thirsty animal that seeks the stream. These hooks help the serpent to maintain a fixed point; they become a fulcrum which gives a double power to his energies. Dr. Mayer detected these rudiments of limbs, and has well explained their anatomy*. He makes boa the first genus of his family of Phænopoda (Ophidians having the rudiments of a foot visible externally), adding the genera Python, Eryx, Tortrix. After adverting to what Merrem, Schneider, Russel, Lacepède. Daudin, Oppel, Cuvier, Oken, and Blainville have said or figured relative to these hooks

Dr. Mayer's paper appeared in the Trans. Soc. Nat. Curios.; and was afterwards translated in the Annales des Sciences for 1826. But Cuvier, whose second edition of the Règne Animal was published in 1829, does not notice it.

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We here have a representation of the osteology of this rudimentary limb, taken from the same author. Figure 2. represents the left posterior limb of the Boa Scy tale, seen anteriorly: a, tibia or leg-bone; b, external bone of the tarsus; c, internal bone of the tarsus; d, bone of the metatarsus with its apophysis; e, nail or hook.

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Figure 3 represents the same limb, seen posteriorly. Doctors Hopkinson and Pancoast have given in the Transactions of the American Philosophical Society, held at Philadelphia, for promoting useful knowledge (vol. v. new series, part i.), an interesting account of the visceral anatomy of the Python (Cuvier), described by Daudin as the Boa reticulata. And here it may be as well to remark that the differences between the Bore and the Pythons are so small, that the accounts given of the constricting powers and even of the principal anatomical details of the one, may be taken as illustrative of the same points in the history of the other. We select from the paper above mentioned an account of the respiratory and urinary organs, because their structure appears to be peculiarly adapted to the habits of the animal.

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Each

'The larynx consists of a single cartilage, having a narrow oblique slit in it, about six lines in length, for the transmission of air; the trachea is one foot eight inches in length, and three-eighths of an inch in diameter, and passes down attached to the ventral face of the oesophagus. It consists of a great number of imperfect cartilaginous rings, interrupted posteriorly, but joined by an elastic substance which keeps their extremities in contact. ring is connected to the adjoining one by a membrane also elastic, so that when the trachea is stretched lengthwise, it will easily regain its former condition. It passes behind the heart, and while there concealed, divides into two bronchiæ, appropriated to the two lungs. The lungs, in a collapsed state, lie much concealed, being covered in part by the liver; but when inflated, are brought into view, and cause the liver to be raised up. These organs consist in two distinct vesicles or bags, united above along their middle, but terminating below, each in a separate cul de sac. They differ materially in size, but vary less in this respect than those of snakes in general. The right lung is two feet ten inches long, and about four inches broad, and extends down as far as the gall-bladder; opposite the spleens,

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which are on its left, it has a considerable contraction of its
diameter. The smaller vesicle lies on the left side, and is
loose at its lower end; it is only one foot nine inches long,
and three inches broad; it terminates near the lower ex-
tremity of the liver. The lower four-fifths of each lung are
thin, semi-transparent, and supplied with fewer blood-vessels
than the upper portion. The parietes are marked by circular
lines or striæ, along which are strung small white bodies,
apparently vesicular, from half a line to two lines distant
from each other; they are much more numerous above, and
appear to be merely attached to the inner surface. The
upper portion of each lung is composed of a more spongy
structure; the parietes are much thicker, and present on
their inner surface a loose reticulated texture, somewhat
resembling a section of the corpus cavernosum penis, the
cells however being much larger. A free passage is left
through the centre, so that the air, in inspiration, is not
obliged necessarily to pass through the cells, which seem to
present merely a more extensive surface for the purposes of
respiration. Both lungs contained many worms, found
most abundant above among the cells, and even in the
trachea; they were of various dimensions, being from one
to three inches in length, whitish, cylindrical, tapering, and
surrounded in their whole length by elevated rings or cords.
The authors of the foregoing description do not seem to
have observed a part of the mechanism of the organs of
respiration detected by Joseph Henry Green, Esq., F.R.S.,
&c. That gentleman, in his lectures at the Royal College
of Surgeons, after alluding to Mr. Broderip's paper on the
mode in which the boa constrictor takes its prey, and of the
adaptation of its organization to its habits, hereinafter given,
and especially that part where the author states that the
larynx is, during the operation of swallowing, protruded
beyond the edge of the dilated lower jaw, exhibited a drawing
of two muscles which he had detected in the lower jaw for
the purpose of bringing the larynx forward, in consequence
of his attention having been drawn to the point by the
statement made in the paper.

Without going into a detail of the anatomy of the other
organs given by Drs. Hopkinson and Pancoast, it will
be sufficient to remark that they detected a peculiarity of
structure which suggests the idea that it is intended to ob
viate the injurious effects of an impeded circulation when
the stomach is distended with food; a disteniton, from the
habits of the animal, likely to be great and of long duration.
Under such circumstances they remark that the peculiarly
constructed vessels may, by a circuitous route, carry a large
proportion of blood to the heart, which the vena cava alone
would be unable to accomplish in a state of partial com-
pression.

Having endeavoured to give the reader some insight into the organization of these serpents, we now proceed to lay before him descriptions by eye-witnesses of the manner in which that organization is brought into action for the purpose of killing and swallowing their prey.

Mr. M'Leod, in his Voyage of H.M.S. Alceste,' gives the following painfully vivid account of a serpent, a native of Borneo, sixteen feet long, and of about eighteen inches in circumference, which was on board. There were originally two; but one, to use Mr. M'Leod's expression, sprawled overboard and was drowned.'

During his stay at Ryswick,' says Mr. M'Leod, speaking of the survivor, he is said to have been usually entertained with a goat for dinner, once in every three or four weeks, with occasionally a duck or a fowl by way of a dessert. The live-stock for his use during the passage, consisting of six goats of the ordinary size, were sent with him on board, five being considered as a fair allowance for as many months. At an early period of the voyage we had an exhibition of his talent in the way of eating, which was publicly performed on the quarter-deck, upon which his crib stood. The sliding part being opened, one of the goats was thrust in, and the door of the cage was shut. The poor goat, as if instantly aware of all the horrors of its perilous situation, immediately began to utter the most piercing and distressing cries, butting instinctively, at the same time, with its head towards the serpent, in self-defence.

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The snake, which at first appeared scarcely to notice the poor animal, soon began to stir a little, and, turning his head in the direction of the goat, he at length fixed a deadly and malignant eye on the trembling victim, whose agony and terror seemed to increase; for, previous to the snake seizing his prey, it shook in every limb, but still continuing

its unavailing show of attack, by butting at the serpent, which now became sufficiently animated to prepare for the banquet. The first operation was that of darting out his forked tongue, and at the same time rearing a little his head; then suddenly seizing the goat by the fore-leg with his fangs, and throwing it down, it was encircled in an instant in his horrid folds. So quick indeed and so instantaneous was the act, that it was impossible for the eye to follow the rapid convolution of his elongated body. It was not a regular screw-like turn that was formed, but resembling rather a knot, one part of the body overlaying the other, as if to add weight to the muscular pressure, the more effectually to crush the object. During this time he continued to grasp with his fangs, though it appeared an unnecessary precaution, that part of the animal which he had first seized. He then slowly and cautiously unfolded himself, till the goat fell dead from his monstrous embrace, when he began to prepare himself for swallowing it. Placing his mouth in front of the dead animal, he commenced by lubricating with his saliva that part of the goat, and then taking its muzzle into his mouth, which had, and indeed always has, the appearance of a raw lacerated wound, he sucked it in, as far as the horns would allow. These protuberances opposed some little difficulty, not so much from their extent as from their points; however, they also in a very short time disappeared, that is to say, externally; but their progress was still to be traced very distinctly on the outside, threatening every moment to protrude through the skin. The victim had now descended as far as the shoulders; and it was an astonishing sight to observe the extraordinary action of the snake's muscles when stretched to such an unnatural extent-an extent which must have utterly destroyed all muscular power in any animal that was not, like himself, endowed with very peculiar faculties of expansion and action at the same time. When his head and neck had no other appearance than that of a serpent's skin stuffed almost to bursting, still the workings of the muscles were evident; and his power of suction, as it is erroneously called, unabated; it was, in fact, the effect of a contractile muscular power, assisted by two rows of strong hooked teeth. With all this he must be so formed as to be able to suspend for a time his respiration; for it is impossible to conceive that the process of breathing could be carried on while the mouth and throat were so completely stuffed and expanded by the body of the goat, and the lungs themselves (admitting the trachea to be ever so hard) compressed, as they must have been, by its passage downwards.

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The whole operation of completely gorging the goat occupied about two hours and twenty minutes, at the end of which time the tumefaction was confined to the middle part of the body, or stomach, the superior parts, which had been so much distended, having resumed their natural dimensions. He now coiled himself up again, and lay quietly in his usual torpid state for about three weeks or a month, when his last meal appearing to be completely digested and dissolved, he was presented with another goat, which he killed and devoured with equal facility. It would appear that almost all he swallows is converted into nutrition, for a small quantity of calcareous matter* (and that perhaps not a tenth part of the bones of the animal), with occasionally some of the hairs, seemed to compose his general fæces....

'It was remarked, especially by the officers of the watch, who had better opportunities of noticing this circumstance, that the goats had always a great horror of the serpent, and evidently avoided that side of the deck on which his cage stood. P. 305.

Mr. Broderip, in the second volume of the Zoological Journal,' after referring to Mr. M'Leod's interesting narrative, of the correctness of which, as far as it goes, he says he has not a single doubt, and observing that two points in that description struck him forcibly, the one as being contrary to the probable structure of the animal, and the other as being contrary to Mr. Broderip's observations, proceeds to give the following account of the manner in which the serpent + takes its prey in this country.

This was most probably the urine of the animal, which is often voided in inspissated lamps, like moist plaster of Paris in appearance, and has been frequently taken for fæces. Dr. John Davy describes it in the Philosophical transactious as of a butyraceous consistence, becoming hard like chalk by exposure to air, and as being a form of pure uric acid.

The serpent whose actions are described by Mr. Broderip, and that which furnished Mr. M'Leod's narrative, were Indian boas or pythons. These have been commonly exhibited under the popular name of Boa constrictor,' and though, as we have already stated, there are points of difference in the arrangement of the scuta below the vent, &c., the general structure of the true South

'Mr. Cops of the Lion Office in the Tower,' writes Broderip, sent to inform me that one of these reptiles had just cast his skin, at which period they, in common with other serpents, are most active and eager for prey. Accordingly I repaired with some friends to the Tower, where we found a spacious cage, the floor of which consisted of a tin case covered with red baize and filled with warm water, so as to produce a proper temperature. There was the snake, "positis novus exuviis," gracefully examining the height and extent of his prison as he raised, without any apparent effort, his towering head to the roof and upper parts of it, full of life, and brandishing his tongue.

the pulmonary system of a boa*, or of satisfying myself as to the structure of the extremely long trachea, which must be very firm to resist such an immense pressure, but I believe, from a near and accurate inspection, in company with others, that respiration goes on during the period of the greatest dilatation. While these serpents are in the act of constringing or of swallowing their prey, they appear to be so entirely pervaded by the optic which then governs them, that I am convinced they would suffer themselves to be cut in pieces before they would relinquish their victim. I have assisted in taking them up and removing them with their prey in their coils, without their appearing to be in the least disturbed by the motion, excepting that, if after the victim is no more and the constriction is somewhat relaxed, an artificial motion be given to the dead body, they instantly renew the constriction. When thus employed they may be approached closely and with perfect security for the reason above stated, and I have uniformly found that the larynx is, during the operation of swallowing, protruded sometimes as much as a quarter of an inch beyond the edge of the dilated lower jaw. I have seen, in company with others, the valves of the glottis open and shut, and the dead rabbit's fur immediately before the aperture stirred, apparently by the serpent's breath, when his jaws and throat were stuffed and stretched to excess. In the case above mentioned, where the prey was taken very awkwardly, and the dilatation was consequently much greater than usual, I saw this wonderful adaptation of means to the exigencies of the animal much more clearly than I had ever seen it before.

'A large buck rabbit was introduced into the cage. The snake was down and motionless in a moment. There he Jay like a log without one symptom of life, save that which glared in the small bright eye twinkling in his depressed head. The rabbit appeared to take no notice of him, but presently began to walk about the cage. The snake suddenly, but almost imperceptibly, turned his head according to the rabbit's movements, as if to keep the object within the range of his eye. At length the rabbit, totally unconscious of his situation, approached the ambushed head. The snake dashed at him like lightning. There was a blow-a scream-and instantly the victim was locked in the coils of the serpent. This was done almost too rapidly for the eye to follow: at one instant the snake was motionless; in the next he was one congeries of coils round his prey. He had seized the rabbit by the neck just under the ear, and was evidently exerting the strongest pressure round the thorax of the quadruped; thereby preventing the expansion of the chest, and at the same time depriving the "With regard to the next point, it is more difficult to acanterior extremities of motion. The rabbit never cried count for the variance between the agony of antipathy after the first seizure: -he lay with his hind legs stretched shown by the goat as described by Mr. M'Leod, and the out, still breathing with difficulty, as could be seen by the indifference which I have uniformly observed in the full motion of his flanks. Presently he made one desperate grown fowls and rabbits presented to these serpents for struggle with his hind legs; but the snake cautiously prey. Immediately after our boa had swallowed his first applied another coil with such dexterity as completely to rabbit, a second was introduced; but the serpent now exhimanacle the lower extremities, and, in about eight minutes, bited a very different appearance. The left side of his the rabbit was quite dead. The snake then gradually and lower jaw was hardly in its place, and he moved about the carefully uncoiled himself, and, finding that his victim cage instead of lying in wait as on the former occasion. As moved not, opened his mouth, let go his hold, and placed for the rabbit, after he had been incarcerated a little while, his head opposite to the fore part of the rabbit. The boa he treated the snake with the utmost contempt, biting it generally, I have observed, begins with the head; but in when in his way, and moving it aside with his head. The this instance the serpent, having begun with the fore-legs, snake, not having his tackle in order, for his jaw was not was longer in gorging his prey than usual, and in conse- yet quite right, appeared anxious to avoid the rabbit, which quence of the difficulty presented by the awkward position at last stumbled upon the snake's head in his walks, and of the rabbit, the dilatation and secretion of lubricating began to treat it so roughly, that the rabbit was withdrawn mucus were excessive. The serpent first got the fore-legs for fear of his injuring the snake. This treatment of the into his mouth; he then coiled himself round the rabbit, snake by the rabbit did not appear to be the effect of anger and appeared to draw out the dead body through his folds; or hatred, but to be adopted merely as a mode of removing he then began to dilate his jaws, and holding the rabbit something, which he did not appear to understand, out of firmly in a coil as a point of resistance, appeared to exercise his way. I have seen many rabbits and fowls presented to at intervals the whole of his anterior muscles in protruding different specimens of boa for prey, and I never saw the his stretched jaws and lubricated mouth and throat at first least symptom of uneasiness either in the birds or quaagainst, and soon after gradually upon, and over his prey. drupeds. They appear at first to take no notice of the The curious mechanism in the jaws of serpents which serpent, large as it is, and when they do discover it they do enables them to swallow bodies so disproportioned to their not start, but seem to treat it with the greatest indifference. apparent bulk is too well known to need description; but it I remember one evening going up into the room where one may be as well to state that the symphysis of the under of these snakes was kept at Exeter Change, and seeing the jaw was separated in this case, and in others which I have hen which was destined for the prey of the boa, very comhad an opportunity of observing. When the prey was comfortably at roost upon the serpent. The keeper took the pletely ingulphed, the serpent lay for a few moments with his dislocated jaws still dropping with the mucus which had lubricated the parts, and at this time he looked quite sufficiently disgusting. He then stretched out his neck, and at the same moment the muscles seemed to push the prey further downwards. After a few efforts to replace the parts, the jaws appeared much the same as they did previous to the monstrous repast.

'I now proceed to the first of the two points above alluded to, and have to state my opinion that the boa constrictor does respire" when his head and neck have no other appearance than that of a serpent's skin stuffed almost to bursting;" and I think that, upon a more close examination, the same phenomenon would have been observable in the serpent shipped at Batavia. It is to be regretted that the dissection of that serpent appears to have been confined to the stomach; at least nothing is said of any other part of the animal. I have never had an opportunity of dissecting American boa so much resembles that of the Indian boa, or python, and the habits of both, particularly in taking their prey, are so similar, that a true description of the predatory habits of the python will give a satisfactory idea of those of the boa,

hen in his hands and held it opposite to the head of the
snake, without succeeding in inducing him to take the bird,
which, when let out of the keeper's hands again, settled
herself down upon the serpent for the night.

The only solution which I can offer of the difference be-
tween Mr. M'Leod's description and my experience, is one
which I do not propose as absolutely satisfactory, but which
may nevertheless be found to approach the truth. The
goats put on board at Batavia for the serpent, which it ap-
pears was brought from Borneo, were in all probability
natives of Java, and if so, they would, according to the
wonderful instinct which nature has implanted in animals
for their preservation, be likely to have a violent antipathy
to large serpents, such as those which there lurk for their
prey. The great Python is a native of Java, and if these
goats were wild, or originally from the wild stock of the
island, their instinctive horror at the sight of the destroyer
may be thus accounted for. But our domestic fowls and
rabbits (the stock of the latter most probably indigenous,
and that of the former of such remote importation, and so
much changed by descent, as to be almost on the same
+ Appetite.

• See ante, p. 22.

See ante, p. 23.

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