| 释义 |
‖ vitellus|vɪˈtɛləs, vaɪ-|
[L. vitellus yolk of an egg.]
1. Embryol. The yolk of an egg; the germinative contents of an ovum-cell.
1728Chambers Cycl. s.v. Egg, In the middle of the inner White, is the Vitellus or Yelk. 1826Good Bk. Nat. (1834) I. 165 In this respect the albumen of the cotyledon corresponds with the vitellus of the hen's egg. 1857Berkeley Cryptog. Bot. xv. 26 Nothing can be more close than the mode of development in these..and of the vitellus in the eggs of certain Mollusca. 1877Huxley Anat. Inv. Anim. 367 In certain Amphipods..the vitellus undergoes complete division.
2. Bot. A fleshy sac situated between the albumen and the embryo in a seed.
1807J. E. Smith Phys. Bot. 292 The Vitellus is esteemed by Gærtner to compose the bulk of the seed in Fuci, Mosses and Ferns. 1829T. Castle Introd. Bot. 245 The vitellus is an organ of a fleshy but firm texture, situated, when present, between the albumen and embryo. 1861Bentley Man. Bot. 444 Embryo minute, enclosed in a vitellus, and outside of abundant fleshy albumen.
b. (See quot.)
1900B. D. Jackson Gloss. Bot. Terms, Vitellus,..an oily substance adhering to the spores of Lycopodium. |