title: [Adaptational evolution of embryogenesis and adult placental individuals].
abstract: On the basis of a comparative morphological and embryological analysis the author concludes that lower mammals (ovipositors and marsupials) and higher mammals should not be united into a single class. Two classes should be distinguished: 1) lower mammals including modern ovipositor animals and marsupial animals and fossilized Multituberculata, Triconodonta, Symmetrodonta and Pantotheria; and 2) higher mammals or placental animals.
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D005075:Biological Evolution; D008322:Mammals / Q000145:classification / Q000196:embryology*; D010920:Placenta / Q000502:physiology
vernacular_title: Prisposobitel'naia évoliutsiia émbriogeneza i vzroslykh osobeĭ platsentarnykh