Pl. thecæ. [L., ad. Gr. θήκη case, cover.]
1. A receptacle, a cell; spec. (Eccl.) = BURSE 1 b.
1662. J. Bargrave, Pope Alex. VII. (1867), 121. Some of these underground streets were for their burials,… the corps were … immuralld in thecas, or, as it were, in hollow shelves dug into the wall.
1682. Lister, trans. Gœdart’s Insects, 95. In this Nest they [Bees] make a Theca, or small Cell…. Every Bee lays 9. little Worms in this Theca, or Cell.
2. Bot. A part of a plant serving as a receptacle; a sac, cell, or capsule; spec. (a) an anther cell, containing pollen; (b) a vessel containing spores in various cryptogamous plants, as the capsule of a moss, the sporangium of a fern, or the fructification in certain lichens.
1676. Grew, Anat. Flowers, II. iii. § 9. These Parts [anthers] are all hollow; each being the Theca or Case of a great many extream small Particles.
1829. Loudon, Encycl. Pl. (1836), 874. Musci.… Thecæ many-seeded, solitary, furnished with an operculum and columella. Ibid., Gloss., Thecæ, the cases that contain the sporules of Cryptogamic plants.
1830. Lindley, Nat. Syst. Bot., 307. Sporules, which are enclosed in particular cases called thecæ.
1880. Gray, Struct. Bot., vi. § 6 (ed. 6), 251. The best technical name for anther-sac is that of Theca.
1897. Willis, Flower. Pl. & F., I. 77. The anther has typically two main lobes or thecae.
3. Zool. and Anat. A case or sheath enclosing some organ or part: as
(a) the horny case of an insect pupa; (b) the loose sheath investing the spinal cord; (c) one of the fibrous sheaths in which the digital tendons glide; (d) the sheath of the proboscis of dipterous insects; (e) a cup-like or tubular structure in corals, containing a polyp.
1665–6. Phil. Trans., I. 89. It becomes a Papilio or Butterfly, in the Theca or Case. Ibid. (1670), V. 2099. Some of these Maggots I took out of their Theca or bagg.
1807. Med. Jrnl., XVII. 308. The theca or sheath which encloses the femoral artery, nerve and vein.
1826. Kirby & Sp., Entomol., III. xxxiv. 467. In all [mouths of Dipterous insects], the theca or sheath is present.
1840. E. Wilson, Anat. Vade-M. (1851), 239. In the thecæ of the fingers several small tendinous fasciculi are generally found.
1875. Huxley, in Encycl. Brit., I. 130/2. In the simple aporose corals the calcification of the base and side walls of the body gives rise to the cup or theca.
1899. Allbutt’s Syst. Med., VII. 536. The water-cushion which surrounds the cord within the spinal theca.
Hence Thecal a., of, pertaining to, or of the nature of a theca; Thecate a., having a theca, sheathed.
1847. Druitt, Surg. Vade M. (ed. 4), 544. The tendinous whitlow, or thecal abscess.
1861. J. R. Greene, Man. Anim. Kingd., Cœlent., 160. A thecal corallum, in other Actinozoz, at length comes to be formed.
1876. Tomes, Dental Anat., 107. The tissue whence the dentine papillæ arise blends insensibly with that making up the substance of the thecal fold.
1877. Huxley, Anat. Inv. Anim., iii. 159. The thecal canals of the Millepores.
1891. Cent. Dict., Thecate.
