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Placentalia    
有胎盘类

有胎盘类

Placentalia \Plac`en*ta"li*a\, n. pl. [NL.] (Zool.)
A division of Mammalia including those that have a placenta,
or all the orders above the marsupials.
[1913 Webster]


Mammalia \Mam*ma"li*a\, n. pl. [NL., from L. mammalis. See
{Mammal}.] (Zool.)
The highest class of Vertebrata. The young are nourished for
a time by milk, or an analogous fluid, secreted by the
mammary glands of the mother.
[1913 Webster]

Note: Mammalia are divided into three subclasses;
[1913 Webster] I. {Placentalia}. This subclass embraces
all the higher orders, including man. In these the
fetus is attached to the uterus by a placenta.
[1913 Webster] II. {Marsupialia}. In these no placenta
is formed, and the young, which are born at an early
state of development, are carried for a time attached
to the teats, and usually protected by a marsupial
pouch. The opossum, kangaroo, wombat, and koala are
examples.
[1913 Webster] III. {Monotremata}. In this group, which
includes the genera {Echidna} and {Ornithorhynchus},
the female lays large eggs resembling those of a bird
or lizard, and the young, which are hatched like those
of birds, are nourished by a watery secretion from the
imperfectly developed mammae.
[1913 Webster]


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  • Placentalia - Wikipedia
    Placental mammals (infraclass Placentalia p l æ s ə n ˈ t eɪ l i ə ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia Placentalia contains the vast majority of extant mammals, which are partly distinguished from monotremes and marsupials in that the fetus is carried in the
  • Placental Mammals - Classification Characteristics - AnimalWised
    Placental mammals, also known as Eutheria, are the most diverse and widespread group of mammals on Earth The defining feature of placental mammals is the presence of a placenta, a specialized organ that forms during pregnancy within the mother's uterus
  • Placentals - Definition, Examples, Characteristics, and Picture
    Placental mammals are warm-blooded vertebrates belonging to the infraclass Placentalia They are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia
  • Placentalia - New World Encyclopedia
    Placentalia is a term used in some taxonomic classification schemes for one of the three major branches of mammals that includes extant members, the others being Monotremata (montremes) and Marsupialia (marsupials)
  • Placental mammal | Characteristics Facts | Britannica
    placental mammal, (infraclass Eutheria), any member of the mammalian group characterized by the presence of a placenta, a vascular organ that develops during gestation, which facilitates exchange of nutrients and wastes between the blood of the mother and that of the fetus The placentals include all living mammals except marsupials and monotremes
  • Placentalia | definition of placentalia by Medical dictionary
    placentalia An obsolete term for a subclass of mammals that nourish their young via a placenta, now designated as Eutheria
  • 13 Examples of Placental Mammals (With Pictures)
    Many examples of placental mammals, also called eutherians, have longer gestations and give birth to young that are relatively developed compared to marsupials and monotremes Additionally, these animals have a wider opening at the base of the pelvis, which enables the birth of a large baby in comparison to the mother’s size
  • PLACENTARIES: what are they, characteristics, classification and 50 . . .
    Start by clarifying what are placental mammals, also called simply placental animals Thus, placental animals constitute a taxonomic infraclass (Placentalia) within the broad class that make up the mammals
  • Placental Mammals (Placentalia) - Know Your Mammals
    Placental Mammals comprise the largest group of mammals and are known for giving birth to relatively well-developed young They have a complex placenta that allows for a longer gestation period, giving their offspring a better chance of surviving in a competitive world
  • Eutheria (Placental Mammals) - San Diego State University
    Eutheria (or Placentalia) is the most taxonomically diverse of three branches or clades of mammals, the other two being Metatheria (or Marsupialia) and Prototheria (or Monotremata) When named by Gill in 1872, Eutheria included both marsupials and placentals





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