MARSTRAND, WILHELm, 1810-73; b. Copenhagen; studied art there, at Munich, and at Rome. He attained high rank by his genre paintings, and became a professor and director of the Copenhagen academy. His most meritorious works are, perhaps, " Return of a Society from a Popula-r Festival," and " Erasmus Montanus." IttARSUPIA'LIA, or MARSUPIA'TA, an extensive order or group of mammals, differing essentially from all others in their organization, and especially in their generative system. The animals of this aberrant group originally received the name of anzmalia crumenata, or purse-bearing animals; and the names now employed have a similar signification, being derived from marsupium, a pouch or bag,. This marsupium, or pouch, which is situated on the abdomen of the female, contains the teats, and serves for the protection -of the immature young; and is unquestionably the most marked characteristic of these -.animals. As the different genera of this order live upon various kinds of food—some being herbivorous, others insectivorous, and others, again, purely carnivorous—we find -various modifications of their organs of progression, prehension, and digestiou; but as the most important of these modifications are noticed in the articles on the principal .genera, we shall confine ourselves to the characters common to the group.
The leading peculiarity presented by the skeleton is the presence of the marsupial bones (see 31aNnotAmA), which are attached to the pubis, and are imbedded in the abdom inal muscles. Another constant buf less striking peculiarity is a greater or less inversion of the angle of the lower jaw. The organs of digestion, including the teeth, vary - extremely, according to the nature of the food; a complex stomach and a emeum of con siderable size being present in some, while others (the carnivorous frenera) have a simple stomach and no efecum. The brain is constructed on a simpler typAhan in the placental mammals. The size of the hemispheres is so small that they leave exposed the olfactory _ganglion, the cerebellum, and more or less of the optic lobes, and they are but partially oonnected together by the " fornix" and "anterior commissure," the great cerebral coin missure known as the "corpus callosum" being absent. In accordance with this condi tion of the brain, these animals are all characterized by a low degree of intelligence, and .mo said (when in captivity) not to manifest any sign of recognition of their feeders. It is, however, in the org,ans of generation and mode of reproduction that these animals -es*ially differ from all the ordinary mammals. • Professor Owen, who has done more to elucidate this subject, and indeed the anatomy and physiology of marsupiata gen orally, than any other anatomist, observes that in all the genera of this order the uterus is double, and the introductory passage more or less (sometimes wholly) separated into two lateral canals. Both the aigestive and generative tubes terminate within a common oloaca (q.v.), and there are vanous other points in which these animals manifest their 'affinity to the oviparous vertebrates. The marsupial bones serve important purposes in
oonnection with their generative economy. " In the female," he observes, " they assist in producing a compression of the mammary gland necessmy for the alimentation of a peculiarly feeble offspring, and they defend the abdominal viscera from the pressure of the young as these increase in size during their marsupial existence, and still more when they return to the pouch for temporary shelter," while in the males they are subservient to the reproductive process. The marsupials belong to the aplacental division of the - mammalia (q.v.). The period of their gestation is short (26 days in the Virginian opos sum, and 39 days in the kangaroo), and the young are produced in so immature a state that the earlier observers believed that they were produced like buds from the nipples to which they saw thern attached. The appearance presented by a young kangaroo of one of the largest species, within 12 hours of its being deposited in the pouch, is described by professor Owen (from personal observation in the zoological gardens) as follows: "It resembled a.n earthworm in the color and semi-transparency of its integument, adhered firmly to the point of the nipple, breathed strongly but slowly, and moved its fore-legs when disturbed. The body was bent upon the abdomen, its short tail tucked in between the hind-legs, which were one-third shorter than the fore-legs. The whole length from the nose to the end of the tail, when stretched out, did not exceed one inch and two lines." The mother apparently employs her mouth in placing the young at the nipple, where it remains suspended, involuntarily absorbing milk for a considerable time (prob ably about two months on an average), after which it sucks spontaneously for some months. Although able from the first, by the muscular power of its lips, to adhere firmly to the nipple, it does not possess the strength to obtain the milk by the ordinary process of sucking. In the process it is assisted by the adaptation of a muscle to the mammary gland, which, by contracting, injects the milk from the nipple into the mouth of the adherent fetus; and to prevent the entrance of milk into the air-passage, the larynx is prolonged upwards to the aperture of the posterior nares, where it is closely embraced by the muscles of the soft palate. The air-passage is thus entirely separated from the throat, and the milk passes on either side of the larynx into the esophagus.
Professor Owen has proposed that these animals should be divided into five tribes or groups, viz., sarcophaga, entomophaga, carpophaga, poephaga, and rhizophaga, according to the nature of their food. With the exception of one American and one Malayan genus, all known existing marsupials belong to Australia, Tasmania, and New Guinea.—For further details regarding this order; the reader is referred to Waterhouse's - Natural History of the Mammalia, vol. i., and to Owen's article "3larsupialia" in the Cyclopcedia of Anatomy and Physiology.