INSTRUCTION

RELATIVE

TO ZOOLOGY AN ANTHROPOLOGY

By M. ISIDORE GEOFFROY SAINT-I1ILA.IRE.

Generation of the Pouch-Animals. — Mexico and expecially Brazil produce, asit is known, several varieties of the Marsupial Mammifers, all the family of theDidelphides, but some, such as the Didelphes, provided with a true pouch, other,such as the Micoures and the Ilermiures, without pouch properly so called, dou-btless it will be possible to procure live specimens of both sexes. We cannottoo strongly urge the naturalist to neglect nothing to clear up the mystery, yethut partially penetrated, of the manner these mammifers reproduce kind. Weare far indeed, from the period, when it was believed that the animals were for-med at the dugs of their dams. The labors of Hunter, Home, Gcoffroy Saint-Hilaire de Blainville and other observers, have long since removed from sciencethis inadmissible anomaly; some years ago, M. Owen, having the fortunate op-portunity of examining the uterus of a female Kanguroo, that died in bringingforth, and of dissecting the embryo it contained has developped several facts ofgreat interest.

But the intra uterine gestation of the marsupials, and the second singular ges-tation peculiar to them, still remain new and important subjects of study for ana-tomy and comparative physiology. Animals or parts of animals sent in alcoholfrom America , the Indian Archipelago, or New-Holland, some cases of reproduc-tion oceuring in Paris and London , such are the imperfect elements which theFrench and English physiologists possess; their efforts to procure a certain num-ber of specimens have always been unsuccessful. This determined Geoft'roySaint-Hilaire to draw 7 up in 1824, and the administration of the museum to sendto all the countries where the Marsupials are found, detailed information on the stateof the question at that time, and of the researches imperiously required by thewants of science from observers in those regions.

1° If learned naturalists could send a series, so that the evolution of theovula, the embryo, and the egg could be studied from its fecundation to its dis-charge from the uterus, they would thus supply Zootomists with all the elementsof the great work we have just pointed ont.

2° To observe with care the circumstances of the passage of the foetus to thevagina of the pouch.

3° To describe in the most accurate manner the way the foetus clings to theteat. They should determine this by observations of several specimens of differentages, and repeat, if possible, on the Didelphides, the curious experiments madeby Collie and Morgan on the mammary foetus of a Marsurpial of an entirely diffe-rent family.

4° To determine exactly and analyse the liquids contained in the breasts of thedam, and the digestive organs of the mammary foetus.

S° To examine in the living subjects the remarkable arrangement of the res-