66 Virginian Opossum
DIDELPHIS VIRGINIANA.--Shaw. VIRGINIAN OPOSSUM. PLATE LXVI.--FEMALE, and YOUNG MALE seven months old. D. pilis laneis basi albis, apice fuscis; sericeis longis albis; facie, rostro colloque pure albis; auriculis nigris apice flavicantibus; cauda. corpora breviore basi pilosi tota albicante.
CHARACTERS. Hair soft and woolly, white near the roots, tipped with brown; the long hairs white and silky; face near the snout, pure white; ears, black; base and margin, whitish; tail, shorter than the body; base, covered with whitish hair. SYNONYMES. VIRGINIAN OPOSSUM, Pennant, Hist. Quad., vol. ii., p. 18, pl. 63. VIRGINIAN OPOSSUM, Pennant, Arctic Zoology, vol. i., p. 73. SARIGUE DES ILLINOIS, Buff., sup. 6. OPOSSUM AMERICANUS, D'Azara, Quad. du Paraguay. DIDELPHIS VIRGINIANA, Shaw's Zool., vol. i., p. 73. MARSUPIALL AMERICANUM, Tyson, in Phil. Trans., No. 239, p. 105. COWPER, bid., No. 290, p. 1565. OPOSSUM, Catesby's Carolina, p. 120, fig. e. OPOSSUM, Barton's Facts, Observations and Conjectures relative to the gene ration of the Opossum of N. Am., London, 1809 and 1813 POSSUM, Lawson's Carolina, p. 120, fig. e. D. VIRGINIANUS, Harlan, Fauna, p. 119. D. VIRGINIANUS, Godman, vol. ii., p. 7, fig. VIRG. OPOSSUM, Griffith, vol. iii., p. 24. VIRG. OPOSSUM, Dekay, Nat. Hist. N. Y., p. 3, fig. 2, pl. 15. OPOSSUM, Notes on the generation of the virginian Opossum, (Didelphis Virginiana,) J. Bachman, D. D., Transactions of the Acad. of Nat. Sciences, April, 1848, p. 40. Letter from M. Michel, M. D., on the same subject, Trans. Acad. Nat. Sciences, April, 1848, p. 46. DESCRIPTION. Body, stout and clumsy; head, long and conical; snout, pointed: the nostrils at the extremity of the long muzzle open on the sides of a protruberant naked and glandulous surface. Ears, large, thin, and membraneous; mouth, wide, and borders rounded; jaws, weak; eyes, placed high on the forehead, small, and without external lids, oblique; moustaches, on the sides of the face, and a few over the eye, strong and rigid. The tongue is covered with rough papillae. Nails, of moderate length, curved; inner toe on the posterior extremities destitute of a nail and opposable to the other toes, thus forming a kind of hand. Tail, (which may be considered a useful appendage to the legs in aiding the motions of the animal), prehensile and very strong, but capable of involution only on the under side, long, round, and scaly, covered with a few coarse hairs for a few inches from the base, the remainder with here and there a hair scattered between. Soles of the hind feet, covered with large tubercles. The female is furnished with a pouch containing thirteen mammae, arranged in a circle, with one in the centre. The fur is of two kinds, a soft woolly hair beneath, covered by much longer hairs, which are, however, not sufficiently dense to conceal the under coat. The woolly hair is of considerable length and fineness, especially in winter. COLOUR. The woolly hair on the upper surface of the body, when blown aside, is white at the base and black at the tips; the long interspersed hairs are mostly white; a few towards the points exhibit shades of dark brown and black; moustaches, white, and black; eyes, black; ears, black, at base, the borders edged with white to near the extremities, where they are broadly patched with white; snout and toes, flesh coloured; face, neck, and nails, yellowish white; a line of dark brown commences on the forehead, widens on the head, and extends to the shoulders--there is also a line of dark brown under the chest; the feet in most specimens are brownish black; we have seen an occasional one where they were reddish brown; tail, brown. The young differ somewhat in colour from the old: they are uniformly lighter in colour, the head being quite white, with a very distinct black dorsal line commencing faintly on the hind head, and running down the back to near the rump. DIMENSIONS. Inches. A well grown female: From point of nose to root of tail,. . . . . . . . . 15 1/2 Length of tail, . . . . . . . . . . . . . . . 12 Height of ear, . . . . . . . . . . . . . . . 1 7/8 Breadth of ear, . . . . . . . . . . . . . . . 1 1/4 Orifice of the distended pouch in diameter, . . . . . . 15 1/2 Teats measured immediately after the young had been withdrawn, . . . . . . . . . . . . . . . . 1 Weight, 12lbs. Young, ten days old, nostrils open, ears pretty well developed: Length of head and body, . . . . . . . . . . . . 1 1/2 Tail,. . . . . . . . . . . . . . . . . . . 1/2 Weight, 22 grains. HABITS. In our first volume (pp. 111, 112) we have spoken of the curiosity eagerly indulged, and the sensations excited, in the minds of the discoverers of our country, on seeing the strange animals that they met with. Travellers in unexplored regions are likely to find many unheard-of objects in nature that awaken in their minds feelings of wonder and admiration. We can imagine to ourselves the surprise with which the Opossum was regarded by Europeans when they first saw it. Scarcely any thing was known of the marsupial animals, as New Holland had not as yet opened its unrivalled stores of singularities to astonish the world. Here was a strange animal, with the head and ears of the pig, sometimes hanging on the limb of a tree, and occasionally swinging like the monkey by the tail! Around that prehensile appendage a dozen sharp-nosed, sleek-headed young, had entwined their own tails, and were sitting on the mother's back! The astonished traveller approaches this extraordinary compound of an animal and touches it cautiously with a stick. Instantly it seems to be struck with some mortal disease: its eyes close, it falls to the ground, ceases to move, and appears to be dead! He turns it on its back, and perceives on its stomach a strange apparently artificial opening. He puts his fingers into the extraordinary pocket, and lo ! another brood of a dozen or more young, scarcely larger than a pea, are hanging in clusters on the teats. In pulling the creature about, in great amazement, he suddenly receives a gripe on the hand--the twinkling of the half-closed eye and the breathing of the creature, evince that it is not dead, and he adds a new term to the vocabulary of his language, that of "playing 'possum." Like the great majority of predacious animals, the Opossum is nocturnal in its habits. It suits its nightly wanderings to the particular state of the weather. On a bright starlight or moonlight night, in autumn or winter, when the weather is warm and the air calm, the Opossum may every where be found in the Southern States, prowling around the outskirts of the plantation, in old deserted rice fields, along water courses, and oil the edges of low grounds and swamps; but if the night should prove windy or very cold, the best nosed dog can scarcely strike a trail, and in such cases the hunt for that night is soon abandoned. The gait of the Opossum is slow, rather heavy, and awkward; it is not a trot like that of the fox, but an amble or pace, moving the two legs on one side at a time. Its walk on the ground is plantigrade, resting the whole heel on the earth. When pursued, it by no means stops at once and feigns death, as has often been supposed, but goes forward at a rather slow speed, it is true, but as fast as it is able, never, that we are aware of, increasing it to a leap or canter, but striving to avoid its pursuers by sneaking off to some thicket or briar patch; when, however, it discovers that the dog is in close pursuit, it flies for safety to the nearest tree, usually a sapling, and unless molested does not ascend to the top, but seeks an easy resting place in some crotch not twenty feet from the ground, where it waits silently and immoveably, till the dog, finding that his master will not come to his aid, and becoming weary of barking at the foot of the tree, leaves the Opossum to follow the bent of his inclinations, and conclude his nightly round in search of food. Although a slow traveller, the Opossum, by keeping perseveringly on foot during the greater part of the night, hunts over much ground, and has been known to make a circle of a mile or two in one night. Its ranges, however, appear to be restricted or extended according to its necessities, as when it has taken up its residence near a corn field, or a clump of ripe persimmon trees, (Diosperos Virginiana,) the wants of nature are soon satisfied, and it early and slowly carries its fat and heavy body to its quiet home, to spend the remainder of the night and the succeeding day in the enjoyment of a quiet rest and sleep. The whole structure of the Opossum is admirably adapted to the wants of a sluggish animal. It possesses strong powers of smell, which aid it in its search after food; its mouth is capacious, and its jaws possessing a greater number and variety of teeth than any other of our animals, evidencing its omnivorous habits; its fore-paws, although not armed with retractile claws, aid in seizing its prey and conveying it to the mouth. The construction of the hind-foot with its soft yielding tubercles on the palms and its long nailless opposing thumb, enable it to use these feet as hands, and the prehensile tail aids it in holding on to the limbs of trees whilst its body is swinging in the air; in this manner we have observed it gathering persimmons with its mouth and fore-paws, and devouring them whilst its head was downwards and its body suspended in the air, holding on sometimes with its hind-feet and tail, but often by the tail alone. We have observed in this species a habit which is not uncommon among a few other species of quadrupeds, as we have seen it in the raccoon and occasionally in the common house dog--that of lying on its back for hours in the sun, being apparently dozing, and seeming to enjoy this position as a change. Its usual posture, however, when asleep, is either lying at full length on the side, or sitting doubled up with its head under its fore-legs, and its nose touching the stomach, in the manner of the raccoon. The Opossum cannot be called a gregarious animal. During summer, a brood composing a large family maybe found together, but when the young are well grown, they usually separate, and each individual shifts for himself; we have seldom found two together in the same retreat in autumn or waiter. Although not often seen abroad in very cold weather in winter, this animal is far from falling into that state of torpidity to which the marmots, jumping mice, and several other species of quadrupeds are subject. In the Southern States, there are not many clear nights of starlight or moonshine in which they may not be found roaming about; and although in their farthest northern range they are seldom seen when the ground is covered with snow, yet we recollect having come upon the track of one in snow a foot deep, in the month of March, in Pennsylvania; we pursued it, and captured the Opossum in its retreat--a hollow tree. It may be remarked, that animals like the Opossum, raccoon, skunk, &c., that become very fat in autumn require but little food to support them through the winter, particularly when the weather is cold. The Opossum, although nocturnal in its general habits, is not unfrequently, particularly in spring and summer, found moving about by day. We have on several occasions met with it in the woods at mid-day, in places where it was seldom molested. Nature has wisely provided this species with teeth and organs indicating its omnivorous character and its possessing an appetite for nearly all kinds of food; and in this particular it exhibits many of the propensities and taster, of the raccoon. It enters the corn fields (maize), crawls up the stalks, and sometimes breaks them down in the manner of the raccoon, to feed on the young and tender grains; it picks up chesnuts, acorns, chinquapins and beach nuts, and munches them in the manner of the bear. We have, on dissection, ascertained that it had devoured blackberries, whortleberries, and wild cherries, and its resort to the persimmon tree is proverbial. It is also insectivorous, and is seen scratching up the leaves in search of worms, and the larvae of insects, of which it is very fond. In early spring it lays the vegetable kingdom under contribution for its support, and we have observed it digging up the roots of the small atamamasco lily, (Zepherina atamasco,) and the young and tender shoots of the China brier, (Smilax rotundifolia,) as they shoot out of the ground like asparagus. It is moreover decidedly carnivorous, eating young birds that it may detect on the ground, sucking the eggs in all the partridge, towheebunting and other nests, it can find in its persevering search. It destroys mice and other rodentia, and devours whole broods of young rabbits, scratching about the nest and scattering the hair and other materials of which it was composed. We have observed it squatting in the grass and brier thickets in Carolina, which are the common resort of the very abundant cotton rat, (sigmodon hispidum,) and from patches of skin and other mutilated remains, we satisfied ourselves that the Opossum was one among many other species designed by Providence to keep in check the too rapid increase of these troublesome rats. We must admit that it sometimes makes a sly visit to the poultry house, killing a few of the hens and playing havoc among the eggs. The annoyances of the farmer, however, from this mischievous propensity, are not as great as those sustained from some of the other species, and cannot for a moment be compared with the destruction caused by the weasel, the mink, or the skunk. The domicile of the Opossum in which it is concealed during the day, and where it brings forth its young, which we have often examined, is found in various localities. This animal is a tolerable digger, although far less expert in this quality than the Maryland marmot, its den is usually under the roots of trees or stumps, when the ground is so elevated as to secure it from rains and inundations. The hollow of a large Fallen tree, or an opening at the roots of a standing one, also serve as a convenient place for its nest. The material which we have usually found composing this nest along the seaboard of Carolina is the long moss (Tillandsia usnoides); although we have sometimes found it composed of a bushel or more of oak and other leaves. On firing into a squirrel's nest which was situated in the fork of a tree some forty feet from the ground, we brought down an Opossum, which had evidently expelled its legitimate occupant. The Florida rat is known to collect heaps of sticks and leaves, and construct nests sometimes a yard in diameter and two feet high: these are usually placed on the ground, but very frequently on the entangled vines of the grape, smilax, and supple jack, (Ziziphus volubilis.) In these nests an Opossum may occasionally be found, dozing as cozily as if he had a better right than that of mere possession. Hunting the Opossum is a very favourite amusement among domestics and field labourers on our Southern plantations, of lads broke loose from school in the holidays, and even of gentlemen, who are sometimes more fond of this sport than of the less profitable and more dangerous and fatiguing one of hunting the gray fox by moonlight. Although we have never participated in an Opossum hunt, yet we have observed that it afforded much amusement to the sable group that in the majority of instances make up the hunting party, and we have on two or three occasions been the silent and gratified observers of the preparations that were going on, the anticipations indulged in, and the excitement apparent around us. On a bright autumnal day, when the abundant rice crop has yielded to the sickle, and the maize has just been gathered in, when one or two slight white hosts have tined the fields and woods with a yellowish hue, ripened the persimmon, and caused the acorns, chesnuts and chinquapins (Castanea pumilla) to rattle down from the trees and strewed them over the ground, we hear arrangements entered into for the hunt. The Opossums have been living on the delicacies of the season, and are now in fine order, and some are found excessively fat; a double enjoyment is anticipated, the fun of catching and the pleasure of eating this excellent substitute for roast pig. "Come, men," says one, "be lively, let us finish our tasks by four o'clock, and after sundown we will have a 'possum hunt." "Done," says another, "and if an old coon comes in the way of my smart dog, Pincher, I be bound for it, he will shake de life out of him." The labourers work with increased alacrity, their faces are brightened with anticipated enjoyment, and ever and anon the old familiar song of "'Possum up the gum tree" is hummed, whilst the black driver can scarcely restrain the whole gang from breaking out into a loud chorus. The paraphernalia belonging to this hunt are neither showy nor expensive. There are no horses caparisoned with elegant trappings no costly guns imported to order--no pack of hounds answering to the echoing horn; two or three curs, half hound or terriers, each having his appropriate name, and each regarded by his owner as the best do, on the plantation, are whistled up. They obey the call with alacrity, and their looks and intelligent actions give evidence that they too are well aware of the pleasure that awaits them. One of these humble rustic sportsmen shoulders an axe and another a torch, and the whole arrangement for the hunt is completed. The glaring torch-light is soon seen dispersing the shadows of the forest, and like a jack o'lantern, gleaming along the skirts of the distant meadows and copses. Here are no old trails on which the coldnosed hound tries his nose for half an hour to catch the scent. The tongues of the curs are by no means silent-ever and anon there is a sudden start and an uproarious outbreak: "A rabbit in a hollow, wait, boys, till I twist him out with a hickory." The rabbit is secured and tied with a string around the neck: another start, and the pack runs off for a quarter of a mile, at a rapid rate, then double around the cotton fields and among the ponds in the pine lands--"Call off your worthless dog, Jim, my Pincher has too much sense to bother after a fox." A loud scream and a whistle brings the pack to a halt, and presently they come panting to the call of the black huntsman. After some scolding and threatening, and resting a quarter of an hour to recover their breath and scent, they are once more hied forwards. Soon a trusty old dog, by an occasional shrill yelp, gives evidence that he has struck some trail in the swamp. The pack gradually make out the scent on the edges of the pond, and marshes of the rice fields, grown up with willows and myrtle bushes (Myrica cerifera). At length the mingled notes of shrill and discordant tongues give evidence that the game is up. The race, though rapid, is a long one, through the deep swamp, crossing the muddy branch into the pine lands, ,where the dogs come to a halt, unite in conclave, and set up an incessant barking at the foot of a pine. "A coon, a coon! dint I tell you, "says Monday," that if Pincher come across a coon, he would do he work?" An additional piece of split lightwood is added to the torch, and the coon is seen doubled up in the form of a hornet's nest in the very top of the long-leaved pine, (P. palustris). The tree is without a branch for forty feet or upwards, and it is at once decided that it must be cut down: the axe is soon at work, and the tree felled. The glorious battle that ensues, the prowess of the doles, and the capture of the coon, follow as a matter of course. See our article on the raccoon, pp. 80, 81, where we have briefly described such a scene. Another trail is soon struck, and the dogs all open upon it at once: in an instant they rush, pell mell, with a loud burst of mingled tongues, upon some animal along the edge of an old field destitute of trees. It proves to be an Opossum, detected in its nightly prowling expedition. At first, it feigns death, and, rolling itself into a ball, lies still on the ground; but the dogs are up to this "'possum playing," and seize upon it at once. It now feels that they are in earnest, and are not to be deceived. It utters a low growl or two, shows no fight, opens wide its large mouth, and, with few struggles, surrenders itself to its fate. But our hunters are not yet satisfied, either with the sport or the meat: they have large families and a host of friends on the plantation, the game is abundant, and the labour in procuring it not fatiguing, so they once more hie on the dogs. The Opossum, by its slow gait and heavy tread, leaves its foot-prints and scent behind it on the soft mud and damp grass. Another is soon started, and hastens up the first small gum, oak, or persimmon tree, within its reach; it has clambered up to the highest limb, and sits crouching up with eyes closed to avoid the light. "Off jacket, Jim, and shake him down; show that you know more about 'possum than your good-for-nutten fox-dog." As the fellow ascends, the animal continues mounting higher to get beyond his reach; still he continues in pursuit, until the affrighted Opossum has reached the farthest twig on the extreme branches of the tree. The negro now commences shaking the tall pliant tree top; while with its hind hands rendered convenient and flexible by its opposing thumb, and with its prehensile tail, the Opossum holds on with great tenacity. But it cannot long resist the rapidly accumulating jerks and shocks: suddenly the feet slip from the smooth tiny limb, and it hangs suspended for a few moments only by its tail, in the meantime trying to regain its hold with its hind hands; but another sudden jerk breaks the twig, and down comes the poor animal, doubled up like a ball, into the opened jaws of eager and relentless canine foes; the poor creature drops, and yields to fate without a struggle. In this manner half a dozen or more Opossums are sometimes captured before midnight. The subsequent boasts about the superior noses, speed and courage of the several dogs that composed this small motley pack--the fat feast that succeeded on the following evening, prolonged beyond the hour of midnight, the boisterous laugh and the merry song, we leave to be detailed by others, although we confess we have not been uninterested spectators of such scenes. "Let not ambition mock their useful toil, "Their homely joys and destiny obscure, "Nor grandeur hear with a disdainful smile, "The simple pleasures of the humble poor." The habit of feigning death to deceive an enemy is common to several species of quadrupeds, and we on several occasions witnessed it in our common red fox (Y. Fulvus). But it is more strikingly exhibited in the Opossum than in any other animal with which we are acquainted. When it is shaken from a tree and falls among grass and shubbery, or when detected in such situations, it doubles itself into a heap and feigns death so artfully, that we have known some schoolboys carrying home for a quarter of a mile an individual of this species, stating that when they first saw it, it was running on the ground, and they could not tell what had killed it. We would not, however, advise that the hand should on such occasions be suffered to come too familiarly in contact with the mouth, lest the too curious meddler should on a sudden be startled with an unexpected and unwelcome gripe. This species has scarcely any note of recognition, and is remarkably silent; when molested, it utters a low growl; at other times its voice resembles the hissing of a cat. The Opossum displays no cunning in avoiding traps set to capture it, entering almost any kind of trap, very commonly being taken in a log trap called a dead fall. From its very prolific nature it can afford to have many enemies. In addition to the incessant war waged against it by men and dogs, we have ascertained that its chief enemy among rapacious birds is the Virginian owl, (Strix Firginiana,) which flying abroad at the same hour in which the Opossum is on foot, pounces on it, and kills it with great ease. We have heard of an instance in which it was seen in the talons of the white-headed eagle, (Halictus leucocephalus,) and of two or three in which the great henhawk (F. Borealis) was observed feeding upon it. We recollect no instance of its having been killed by the wild cat or the fox. The wolf, it is said, seizes on every Opossum it can find, and we have heard of two instances where half-grown animals of this species were found to have been swallowed by the rattlesnake. Although the dog hunts it so eagerly, yet we have never been able to ascertain that it ever feeds upon its flesh; indeed, we have witnessed the do, passing by the body of a fresh killed Opossum, and going off half a mile farther to feed on some offensive carcase. The Opossum is easily domesticated when captured young. We have, in endeavouring to investigate one of the very extraordinary characteristics of this species, preserved a considerable number in confinement, and our experiments were continued through a succession of years. Their nocturnal habits were in a considerable degree relinquished, and they followed the servants about the premises, becoming troublesome by their familiarity and their mischievous habits. They associated familiarly with a dog on the premises, which seemed to regard them as necessary appendages of the motley group that constituted the family of brutes in the yard. They devoured all kinds of food: vegetables, boiled rice, hominy, meat both raw and boiled, and the scraps thrown from the kitchen; giving the preference to those that contained any fatty substance. On one occasion a brood of young with their mother made their escape, concealed themselves under a stable, and became partially wild; they were in the habit of coming out at night, and eating scraps of food, but we never discovered that they committed any depredations on the poultry or pigeons. They appeared however to have effectually driven off the rats, as during the whole time they were occupants of the stable, we did not observe a single rat on the premises. It was ascertained that they were in the habit of clambering over fences and visiting the neighbouring lots and gardens, and we occasionally found that we had repurchased one of our own vagrant animals. They usually, however, returned towards daylight to their snug retreat, and we believe would have continued in the neighbourhood and multiplied the species had they not in their nightly prowlings been detected and destroyed by the neighbouring dogs. A most interesting part of the history of this animal, which has led to the adoption of many vulgar errors, remains to be considered, viz., the generation of the Opossum. Our investigations on this subject were commenced in early life, and resumed as time and opportunity were afforded, at irregular, and sometimes after long intervals, and were not satisfactorily concluded until within a month of the period of our writing this article, (June, 1849). The process by which we were enabled to obtain the facts and arrive at our conclusions is detailed in an article published in the Transactions of the Academy of Natural Sciences,. April, 1848, p. 40. Subsequent investigations have enabled us to verify some or these facts, to remove some obscurities in which the subject was yet involved, and finally to be prepared to give a correct and detailed history of a peculiarity in the natural history of this quidruped, around which there has hitherto been thrown a cloud of mystery and doubt. Our early authors--MARCGRAVE, PISON, VALENTINE, BEVERLY, the MARQUIS OF CHASTELLUX, PENNANT, and others, contended that "the pouch was the matrix of the young Opossum, and that the mammae are, with regard to the young, what stalks are to their fruits." DE BLAINVILLE and Dr. BARTON speak of two sorts of gestation, one uterine and the other mammary. BLUMENBACH calls the young when they are first seen on the mammae, abortions; and Dr. BARTON's views (We quote from GRIFFITH) are surprisingly inaccurate: "The Didelphes," he says, "put forth, not foetuses but gelatinous bodies; they weigh at their first appearance generally about a grain, some a little more, and seven of them together weighed ten grains." In 1819, GEOFFROY St. HILLAIRE propounded to naturalists the following question: "Are the pouched animals born attached to the teats of the mother?" GODMAN, in his American Natural History, published in 1826, gave to the world a very interesting article on the Opossum, full of information in respect to the habits, &c., comprising all the knowledge that existed at that day in regard to this species. He was obliged, however, to admit, vol. 2, p. 7, "the peculiarities of its sexual intercourse, gestation, and parturition, are to this day involved in profound obscurity. Volumes of facts and conjectures have been written on the subject, in which the proportion of conjecture to fact has been as a thousand to one, and the difficulties still remain to be surmounted." And DEKAY, in the work on the Quadrupeds of the State of N. York, (Nat. Hist. of N. York, 1842, p. 4,) states: "The young are found in the external abdominal sac, firmly attached to the teat in the form of a small gelatinous body, not weighing more than a grain. It was along time believed that there existed a direct passage from the uterus to the teat, but this has been disproved by dissection. Another opinion is, that the embryo is excluded from the uterus in the usual manner and placed by the mother to the teat; and a third, that the embryo is formed where it is first found. Whether this transfer actually takes place, and if so, the physiological considerations connected with it, still remain involved in great obscurity." The approaches to truth in these investigations have been very gradual, and the whole unusually slow. COWPER, TYSON, DE BLAINVILLE, HOME and others, by their examinations and descriptions of the organs of the Marsupialiae, prepared the way for farther developments. A more judicious examination and scientific description by OWEN and others, of the corresponding organs in the kangaroo, the largest of all the species composing these genera, and the discovery of the foetus in utero, enabled naturalists to conclude, that the similar structure in the Opossum would indicate a corresponding result. No one, however, was entitled to speak with positive certainty until the young were actually detected in the uterus, nor could an explanation of the peculiarity in the growth of the foetus be made until it was examined in its original bed. We have been so fortunate in five instances as to have procured specimens in which the young were observed in this position, and therefore feel prepared to speali with certainty. We are not aware that the young of the Virginian Opossum had been previously detected in the uterus. All our investigations were made in South Carolina, where this is a very abundant species. For some years we attempted to arrive at the object of our researches by preserving these animals in a state of confinement. But they were subject to many accidents: they frequently made their escape from their canes, and some of them became overburdened with fat and proved sterile, so that we did not succeed in a single instance in obtaining young from females in a state of confinement. From this cause the naturalists of Europe, and especially those of France, who were desirous of making investigations in regard to our Opossum, have been so long unsuccessful. Their usual complaint has been, "Your Opossums do not breed in confinement." In this, Dr. BARTON and our young friend Dr. MICHEL were more fortunate, but in both cases the young were produced before they were enabled to detect them in their previous existing position. We varied our experiments by endeavouring to discern the precise period when young were usually produced. We ascertained, by having a number of females procured with young in their pouches, that about the close of the first week in March, a little earlier or later, according to the age of the individual, or warmth, or coldness, of the previous winter, was the time when in this latitude this event usually occurs. Here, however, another difficulty presented itself, which for several successive seasons, thwarted us in our investigations. In the third week of February 1847, by offering premiums to the servants on several neighbouring plantations we obtained in three nights thirty-five Opossums, but of that number there was not a single female. A week afterwards, however, when the young were contained in the pouch, we received more females than males. From this circumstance we came to the conclusion that during the short period of gestation, the females, like those of some other species of quadrupeds, particularly the American black bear, conceal themselves in their burrows and can seldom be found. We then changed our instructions for capturing them, by recommending that they should be searched for in the day time, in hollow logs and trees and places where they had been previously known to burrow. By this means we were enabled at different times to obtain a small number in the state in which we were desirous of examining them. We feel under great obligations to several gentlemen of Carolina for aiding us in our investigations by procuring specimens, especially our relative Colonel HASKELL, Mr. JOHNSON, and JAMES FISHER, Esq., a close observer and intelligent naturalist. The latter, by his persevering efforts, pursued for some years at Jordan's Mills, on the upper waters of the Edisto, obtained two females in May, 1849, in the particular state in which be knew we were anxious to procure them, and brought them to us without having been previously aware that we had published the facts a year before. The Opossums we were enabled to examine were dissected on the 11th, 14th and 18th February, 1848, and on the 12th and 22d May, 1849. Some of these had advanced to near the time of parturition. The young of those brought us by Mr. FISHER each weighed 2 1/2 grains. Those of one, sent us by Col. HASKELL, weighed 3 grains; and the young of another which we obtained by a Caesarian operation, at a moment when all the rest had been excluded, and this individual alone remained, weighed 4 grains. We remarked, that this however was a little the largest of six that composed the family, five of which were already in the pouch and attached to the teats. The largest one weighed 3 3/4, and another 3 1/2 grains. The weight, then, of the young Opossum at the moment of birth, is between 3 and 4 grains, varying a little in different specimens as is the case in the young of all animals. The degree of life and animation in young Opossums at the moment of birth has been greatly underrated. They are neither abortions, as BLUMENBACH represented them, nor as Dr. BARTON has described them--"not foetuses, but gelatinous bodies, weighing about a grain more or less, seven of them together weighing 10 grains"--but little creatures that are nearly as well developed at birth as the young of the white-footed mouse and several other species ot rodentia. They are covered by an integument, nourished by the mammae, breathe through nostrils, perform the operations of nature, are capable of a progressive movement at the moment of their birth, and are remarkably tenacious of life. The individual which was dissected from the parent in the manner above detailed, moved several inches on the table by crawling and rolling, and survived two hours; the thermometer in the room was at the time standing at 66 degrees Fahrenheit. The period of gestation is from fifteen to sixteen days. We received a female from a servant who informed us, that be had that morning seen it in intercourse with the male. We first saw the young on the morning of the 17th day. Our friend Dr. MIDDLETON MICHEL, a gentleman of high scientific attainments, and who had long been engaged in investigating the characters and habits of this species, in a communication made to us, (Trans. of the Acad. Nat, Sciences, April, 1848, p. 46,) assured us from his personal observation in which he was careful to note the hour of the day, the exact period is 15 days. As be possessed better opportunities of deciding in regard to the time, the animals being in a state of domestication, we are rather more disposed to yield to his observations than to our own; there is, however, only the difference of a day between us. The young, when first born, are naked and flesh-coloured; the eyes, together with the ears, are covered by a thin integument through which these organs and the protuberances of the ears are distinctly visible. The mouth is closed, with the exception of a small orifice, sufficiently large to receive the teat, which is so thin and attenuated that it seems no larger than the body of a pin. Length of body, 7-12ths of an inch; of tail, 2-10ths. The nails, which can be seen with the naked eye, are very distinct when viewed with a microscope, and are of a dark brown colour, small and much hooked. The nostrils are open; the lungs filled with air, and when placed in water, the young float on the surface. The number of young usually found in the pouch appear to be less than those that are born. The highest number we have found in the pouch was thirteen, the smallest six; whereas the preserved uterus brought to us by Mr. FISHER, contained fifteen. In all such cases, where a greater number of young are produced than there are teats, the last of the brood must inevitably perish, as those that are attached appear incapable of relinquishing their hold. The manner in which the young at birth reach the pouch, and become attached to the teats, has been the subject of much speculation and inquiry. We had an opportunity of examining this process in part, without, however, having been aware at the time that it was going on. We intended to dissect a small female Opossum, which had been a few days in our possession, but ascertained in the morning at seven o'clock on the day our examination was to have been made, that she had three young in her pouch; supposing from her small size, that she would produce no additional number, we concluded to spare her life. She was confined in a box in our study; when we occasionally looked at her, we found her lying on one side, her shoulders elevated, her body drawn up in the shape of a ball; the pouch was occasionally distended with her paws--in this position the parts reached the edge of the pouch; she was busily employed with her nose and mouth licking, as we thought, her pouch, but in which we afterwards ascertained, were her young. At six o'clock in the afternoon we were induced to examine her again, in consequence of having observed that she had for several hours appeared very restless, when we discovered that she had added four more to her previous number, making her young family now to consist of seven. With no inconsiderable labour and the exercise of much patience, we removed three of the young from the teats, one of which perished under the process, we replaced the two living ones in the pouch; at nine o'clock examined her again and found both the young once more attached. We came to the conclusion, that she shoved them into the pouch, and with her nose or tongue moved them to the vicinity of the teats, where by an instinct of nature, the teat was drawn into the small orifice of the mouth by suction. We observed subsequently, that a young one that had been extracted from its parent a few moments before the time when it would have been born, and which had been rolled up in warm cotton, was instinctively engaged in sucking at the fibres of the cotton, and had succeeded in drawing into its mouth a considerable length of thread. A nearly similar process was observed by our friend Dr. MICHEL. He states: "The female stood on her hind legs, and the body being much bent, the young appeared and were licked into the pouch." There is a great difficulty in deciding the question, whether the mother aids the young in finding the teats, in consequence of the impossibility of the spectators being able to know what she is actually doing, whilst her nose is in the pouch. We believe the majority of naturalists who had an opportunity of witnessing our experiments came to the conclusion, that the mother, after shoving them into the pouch, left them to their own instinct, and they became attached without her assistance. We tried another experiment that suggested itself to us. Believing that the mother would not readily adopt the young of another, or afford them any assistance, we removed six out of ten that composed her brood, returned two of her own to the pouch, together with three others fully double the size, that had been obtained from another female. She was soon observed doubled up with her nose in the pouch, and continued so for an hour, when she was examined and one of her own small ones was found attached to the teat. Seven hours afterwards she was examined again, and both the small ones were attached, but the three larger ones still remained crawling about the pouch. On the following morning, it was ascertained that the mother had adopted the strangers, as the whole family of different sizes were deriving sustenance from her. On another occasion, a female Opossum had been sent to us caught by a dog and much wounded, in consequence of which she died a few days afterwards, but first producing seven young which to every appearance had been still born. Yet they were in the pouch, and it appeared to us that the mother's uncontrollable attachment to her young, induced her to place her offspring in the pouch, even after they were dead. An interesting inquiry remains to be answered: Is the Opossum a placental or non-placental animal? Until we were favoured with a recent opportunity of carefully examining a uterus, containing nine young on one side, and six on the other, kindly brought to us by our friend JAMES FISHER, we were unable fully to answer this question. Our dissections and examinations were witnessed by Professors MOULTRIE, HUME, Drs. HORLBECK MICHEL, PORCHER and others. The Opossum is, as far as we are able to judge from the specimens examined, a non-placental animal, in as much as there could not be detected the slightest adhesion between the exterior membrane of the foetus and the internal surface of the mother. The membranes consisted of a vitelline sac, filled with ramifications of omphalo-mesenteric vessels, there was a slight appearance or an umbilical cord and umbilical vessels, constituting a true allantois, but no portions of them were attached to the uterus. There was no appearance of a placenta. The growth of file young Opossum is suprisingly rapid. We weighed the largest young one at a week old and found it had increased from 3 3/4 grains to 30 grains. Length of head and body exclusive of tail, 1 1/4 inch; tail, 1/2 inch. The young at this age were very tenacious of life, as on removing two, they remained alive on the floor without any covering through a cool night, in a room containing no fire, and still exhibited a slight motion at twelve o'clock on the following day. The teats of the mother after the young had been gently drawn off measured an inch in length, having been much distended, and appeared to have been drawn into the stomach of the young. The pouches of the young females were quite apparent; they used their prehensile tails, which could now be frequently seen entwined around the necks of others. At twelve days old the eyes were still closed, a few hairs had made their appearance on the moustache; the orifice of the ears were beginning to be developed, and the nails were quite visible and sharp. When the young are four weeks old, they begin from time to time to relax their hold on the teats, and may now be seen with their heads occasionally out of the pouch. A week later, and they venture to steal occasionally from their snug retreat in the pouch, and are often seen on the mother's back securing themselves by entwining their tails around hers. In this situation she moves from place to place in search of food, carrying her whole family along with her, to which she is much attached, and in whose defence she exhibits a considerable degree of courage, growling at any intruder, and ready to use her teeth with great severity on man or dog. In travelling, it is amusing to see this large family moving about. Some of the young, nearly the size of rats, have their tails entwined around the legs of the, mother, and some around her neck, thus they are dragged along. They have a mild and innocent look, and are sleek, and in fine condition, and this is the only age in which the word pretty can be applied to the Opossum. At this period, the mother, in giving sustenance to so large a family, becomes thin, and is reduced to one half of her previous weight. The whole family of young remain with her about two months, and continue in the vicinity till autumn. In the meantime, a second and often a third brood is produced, and thus two or more broods of different ages may be seen, sometimes with the mother, and at other times not far off. The Opossum, with the exception of our gray rabbit, is one of the most prolific of our quadrupeds. We consider the early parts of the three months of March, May and July, as the periods in South Carolina when they successively bring forth; it is even probable that they breed still more frequently, as we have observed the young during all the spring and summer months. In the month of May, 1830, whilst searching for a rare species of coleoptera, in removing with our foot some sticks composing the nest of the Florida rat, we were startled on finding our boot unceremoniously and rudely seized by an animal which we soon ascertained was a female Opossum. She had in her pouch five very small young whilst, seven others, about the size of full grown rats were detected peeping from under the rubbish. The females produce young at a year old. The young born in July do not bring forth as early as those born in March, but have their young as soon as the middle of the succeeding May. There is, of course, in this as well as in other species, some degree of irregularity in the time of their producing, as well as in the number of their young. We have reason to believe, also, that this species is more prolific in the southern than in the Middle States. GEOGRAPHICAL DISTRIBUTION. The Hudson River may be regarded as the farthest eastern limit of the Opossum. We have no doubt but that it will in time be found existing to the east of the Hudson, in the southern counties of New-York as well as on Long-Island and the warmer parts of the Eastern States, as the living animals are constantly carried there, and we have little doubt that if it was considered important it could be encouraged to multiply there. It has been stated to us that in New-Jersey, within five or ten miles of New-York, as many as ten or fourteen of these animals have within a few years past been taken in an autumn by means of traps, but that their number is gradually diminishing. It is common in New-Jersey and Pennsylvania, becoming more abundant as we proceed southwardly through North Carolina, South Carolina, Georgia, Louisiana and Texas, to Mexico; inhabiting in great numbers the inter-tropical regions. To the west we have traced it in all the south-western states. It exists in Indiana, Mississippi, Missouri, and Arkansas, and extends to the Pacific; it is said to exist in California. It is somewhat singular, that in every part of America, as far as we have been able to observe, the geographical range of the Opossum is very nearly the same as that of the persimon tree, of whose fruit it is so fond. This we regard, however, as merely accidental, as this food is not essential to its support. The Opossum neither ceases to multiply or to thrive in seasons in which the persimon has failed. GENERAL REMARKS. In our plate, we gave PENNANT as the originator of the scientific name of this species. We find, however, that he only calls it the Virginia Opossum, with a reference to the Didelphys marsupialis, LINNEUS. GMELIN subsequently arranged it under Didelphys marsupialis. As SHAW, in 1800, as far as we have been able to ascertain, seems to have been the first who applied the Latin specific name, D. Virginians, we have, in accordance with the rules laid down by naturalists, given him the credit of the specific name.