Abstract

A method is presented for splitting open fixed blastocysts and mounting the entire vesicle on a flat surface. A description is given of the red kangaroo blastocyst during lactation-controlled embryonic diapause. The protoderm is unilaminar and contains about 85 cells. No mitotic figures are seen, and there is no growth or differentiation. The marsupial blastocyst is compared with blastocysts of eutherian mammals during diapause.