Didelphis marsupialis syn. D. cancrivora syn. Philander cancrivorus Identifier: evolutionofmanpo02hae (
find matches)Title:
The evolution of man: a popular exposition of the principal points of human ontogeny and phylogeneYear:
1896 (
1890s)Authors:
Haeckel, Ernst, 1834-1919Subjects:
Evolution Embryology, Human Anatomy, Comparative Human beingsPublisher:
New York, FowleContributing Library:
Smithsonian Institution LibrariesDigitizing Sponsor:
Biodiversity Heritage LibraryView Book Page:
Book ViewerAbout This Book:
Catalog EntryView All Images:
All Images From Book Click here to
view book online to see this illustration in context in a browseable online version of this book.Text Appearing Before Image:, thesiniple structure of the allantois (which does not as yetdevelop a placenta), with many other characters, have beeninherited by the Pouched Animals from Cloacal Animals.On the other hand, they have lost the independent coracoidbone (os coracoideurri) attached to the shoulder girdle. Amore important step consists in the fact that a cloaca is nolonger formed; the cavity of the rectum, together with theanal opening, is separated by a partition wall from the urinaryand sexual opening (sinus urogenitalis). Moreover, allPouched Animals develop special nipples on the milk-glands,which are sucked by the young after birth. These nipplesproject into the cavity of a pouch, or marsupium, in theventral side of the mother. This pouch is supported bya couple of marsupial bones. In it the young, which are 152 THE EVOLUTION OF MAN bom in a very imperfect condition, are carried by themother foi a long time; until, in fact, they are completelydeveloped (Fig. 197). In the large Giant Kangaroo, whichText Appearing After Image:Fig. 197.—The Crab-eating Pouched Eat (Philander cancrivorus). Afemale with two young in its pouch. (After Brehm.) THE POUCHED ANIMALS AS ANCESTORS OF ItfAN. 1^3 attains the height of a man, the embryo develops in theuterus but for a month; it is then bom in a very incompletecondition, and attains all its further development in themother s pouch, where, for about nine months, it remainsattached to the milk-glands. All these and other characters (especially the peculiarstructure of the internal and external sexual orcrans of themale and female) clearly show that the whole sub-class ofthe Pouched Animals (Marsupialia) are a single group,which originated from the promammalian branch. From abranch of these Pouched Animals (perhaps from severalbranches) the parent-forms- of the higher Mammals, thePlacental Animals, afterwards sprang. Hence we mustreckon a whole series of Pouched Animals among the an-cestors of the human race; and these constitute the seven-teenth stage in the human pedigNote About Images Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.