| 释义 |
‖ cnida Zool.|ˈknaɪdə|
Pl. cnidæ.
[mod.L., a. Gr. κνίδη nettle.]
The nettle cell (urticating, or thread cell) of the Cœlenterata (jelly-fish, hydra, etc.), in which their power of stinging resides: usually called nematocyst. Hence [combining form cnido-], ˈcnidoblast [Gr. βλαστός germ], the cell in which a nematocyst is developed; ˈcnidocell = cnida; ˈcnidocil [L. cilium, cf. cil], the external irritable ciliary process of a cnidoblast; ˈcnidocyst, a nematocyst; cniˈdogenous a., producing or containing nematocysts; ˈcnidophore [Gr. -ϕορος bearing], a process bearing a ‘battery’ of cnidoblasts; ˈcnidosac, the dilated middle part of a tentillum in certain Siphonophora.
1876Macalister Anim. Morphol. 80 In the protoplasmic ectoderm exist scattered or clustered nettle-cells (cnidæ or trichocysts) which are minute oval capsules filled with fluid..lined by a delicate membrane which at the apex is involuted into an axial tube, ending in a long coiled barbed thread. 1884Sedgwick tr. Claus' Elem. Zool. I. 223 Each Cnidoblast..possesses a fine superficial plasmatic process (Cnidocil), which is probably very sensitive to mechanical stimuli and occasions the bursting of the capsule. 1887Rolleston & Jackson Forms Anim. Life 331 The nematocysts are removed from the cells or cnidoblasts in which they were developed, and where they usually remain until discharged. Ibid., The discharge of the thread is therefore brought about through..direct mechanical or chemical irritation of the cnidocil. Ibid. 757 Some of the hydranths are furnished with a single basal horn-like process—the cnidophore—armed terminally with a battery of cnidoblasts. 1888E. Haeckel in Challenger Rep. (Zool.) XXVIII. 259 Large ensiform or spindle-shaped cnidocysts. Ibid., The cnidosac (sacculus or urticating knob) is ovate, spindle-shaped, or pyriform. 1898Sedgwick Text-bk. Zool. I. 146 The swelling of the cnidosac is due to a rich development of nematocysts of various kinds, forming the battery. 1902Encycl. Brit. XXX. 797/1 The hepatic cæca in the dorsal papillæ of Eolidoida actually communicate with the cnidogenous sacs at their extremity; cnidocysts are absent from Eolis glaucoides. 1940Chambers's Techn. Dict. 171/1 Cnidosac, in Siphonophora, a battery of cnidoblasts borne on a tentacle, where it gives rise to a coloured swelling. |