| 释义 |
‖ columella|kɒljuːˈmɛlə|
[L.; = ‘small column’, dim. of columna column. Cf. prec.]
1. Anat.
a. An old name for the uvula.
b. The modiolus or axis of the cochlea of the ear (columella cochleæ): cf. 2.
c. Sometimes applied to other structures of analogous form.
1585Lloyd Treas. Health H iiij, The lytle flap which couerith the wyndpipe called Uvula, some call it Columella. 1689Moyle Sea Chyrurg. ii. xx. 75 Sometimes by cold men have..their Collumella relaxed.
2. Conch. The axis of a spiral shell.
1755Gentl. Mag. XXV. 31 Columella, the interior axis of the shell from top to bottom, round which the spirals are twisted. 1842Proc. Berw. Nat. Club II. x. 32 The shell..perfectly diaphanous, exhibiting the axis or columella very clearly. 1856Woodward Mollusca 100.
3. Bot.
a. ‘The long axis round which the parts of a (dehiscent) fruit are united: in reality, the ripened growing point’ (Treas. Bot.).
1760Lee Botany vi. (1776) 14 (Jod.) The substance which passes through the capsule, and connects the several partitions and seeds, columella. 1887A. W. Bennett tr. Thomé's Bot. (ed. 6) 397 The fruit [of Umbellifers] is a bipartite schizocarp..two halves separating from the columella.
b. The firm centre or axis of the spore-case of an urn-moss.
c. A slender axis over which the spore-cases of such ferns as Trichomanes are arranged. (Treas. Bot.)
1821S. F. Gray Arrangem. Brit. Plants I. 222 Columelle, Columella, Sporangidium. A thread-like pillar in the centre of the urn to which the seeds are attached. 1857Henfrey Bot. §319 A striking peculiarity of the capsule of the Mosses is the existence of this columella, or stalk-like process running up the centre of the cavity of the sporange. 1882Vines Sachs' Bot. 354 The long sporogonium has a longitudinal dehiscence and no columella.
4. Zool.
a. A part of the pterygoid bone in the skull of lizards (columella cranii).
b. A delicate bone in the middle ear of birds, reptiles, and amphibians (columella auris). Cf. 1 b.
c. The central axis or pillar of the visceral chamber of many corals.
1848Dana Zooph. 529 The cells have no distinct columella. 1872Mivart Elem. Anat. 111 In Lizards, a peculiar dismemberment of the pterygoid, called the columella, may ascend and join the parietal. 1872Dana Corals i. 44 The bottom of the calicle..in the corallum is sometimes made simply by the meeting of the radiating septa; occasionally..with the addition of a point or columella at the centre. |