| 释义 |
placental, a. (n.)|pləˈsɛntəl|
[ad. mod.L. placentāl-is, f. prec.: see -al1.]
A. adj.
1. Zool., etc. Of or pertaining to the placenta.
placental murmur, placental sound, placental soufflet, the sound made by the blood entering the distended uterine vessels, heard in auscultation during the later months of pregnancy.
1808Barclay Muscular Motions 367 From a change of function, placental blood is no longer returned to the liver. 1843R. J. Graves Syst. Clin. Med. vii. 84 note, No one who has ever heard the placental soufflet. 1876J. S. Bristowe The. & Pract. Med. (1878) 265 The raw surfaces of wounds or of the placental area. 1893Syd. Soc. Lex., P[eriod], placental, the time occupied in the expulsion of the placenta.
b. Furnished with a placenta; placentate.
1840–45Owen Odontogr. iii. xi. 501 The development of the true molar teeth to their typical number in the placental Mammalia. 1871Darwin Desc. Man. I. vi. 202 The Marsupials stand..below the placental mammals.
2. Bot. Pertaining to the placenta (of a plant).
1857Henfrey Elem. Bot. §227 In Leguminosæ the double placental base is so narrow that the ovules alternate with one another. 1870Hooker Stud. Flora 259 Ovule..flanked by a column of placental tissue.
B. n. Zool. A placental mammal.
1864Webster cites Owen. 1897Pop. Sci. Monthly Nov. 17 The marsupials..have been gradually supplanted by the more highly organized placentals. |