| 释义 |
gemmule|ˈdʒɛmjuːl|
[a. F. gemmule, ad. L. gemmula, dim. of gemma a bud, gem.]
1. Bot.
a. = plumule.
1844Hoblyn Dict. Med., Gemmule, a term used synonymously with plumule, the growing point of the embryo in plants. 1861Bentley Bot. 344 Thus we distinguish three parts in the embryo, corresponding to the root, stem, and leaves of the perfect plant; namely, a radicle, plumule or gemmule, and one or more cotyledons.
b. One of the reproductive cells of cryptogams.
1874Cooke Fungi 55 Short germinating utricles shoot forth, which soon form themselves into rows of gemmules.
2. Zool. A small gem (see gem n. 5) or gemma; spec. a ciliated embryo of one of the Cœlenterata; an encysted mass of sponge-particles, from which new ones are produced. In Darwin's theory of pangenesis, one of the hypothetical units conceived of as capable of reproducing the part from which it is thrown off.
1845Zoologist III. 955 This cell, or germ, or gemmule, is the origin of all existing animals. 1858T. R. Jones Aquar. Nat. 34 These yellow granules are the rudiments of the eggs, or gemmules of the sponge. 1871Darwin Desc. Man I. viii. 280 According to this hypothesis, every unit or cell of the body throws off gemmules or undeveloped atoms. 1872Carpenter Anim. Phys. xv. 562 In this state it becomes clothed with cilia and is termed a gemmule. 1875[see pangenetic a.]. 1877W. Thomson Voy. Challenger I. iii. 176 Small examples of the sponge, some of them not much beyond the condition of gemmules. 1913Q. Rev. Oct. 376 No one now accepts Darwin's theory of gemmules or pangenesis. 1952C. P. Blacker Eugenics ii. 45 According to this provisional hypothesis,..the cells of the body throw off minute particles called gemmules which circulate freely throughout the blood-stream and multiply there.
fig.1869F. Galton Hered. Genius 365 Young artisans, and other floating gemmules of English population. |