Zool. [mod. f. Gr. ἀράχνη spider + -ID; cf. F. arachnide.] A member of the Arachnida. ǁ Arachnida, sb. pl. [mod. L.], a class of the Arthropoda, comprising spiders, scorpions and mites; closely allied to Insects and Crustacea, but distinguished by the possession of eight legs, the absence of wings and antennæ, and by breathing by means of tracheal tubes or pulmonary sacs. Arachnidan, a. of or belonging to the Arachnida: sb. an arachnid. Arachnidean, -ian a. and sb. = prec. Arachnidial a. [f. next] of or pertaining to the Arachnidium. ǁ Arachnidium [mod.L.], the apparatus by which the spider produces its web. Arachnidous a. of the nature of the Arachnida.
1869. Huxley, Classif. Anim., 77. A Crustacean, an *Arachnid, a Myriapod, or an Insect.
1881. Geikie, in Nature, No. 627. 3. There can be little doubt that it [scorpion] is the most ancient type of Arachnid, whence the others have been derived.
1834. Penny Cycl., II. 232/1. The greater number of the *arachnida are carnivorous.
1881. Mivart, Cat, 511. The *arachnidan external parasite is a sort of itch insect.
1828. Kirby & Spence, Entomol., III. xxviii. 51. No genuine insect or Arachnidan has yet been found to inhabit the ocean.
1865. in Morn. Star, 7 Nov. All the rails in front of my residence had their busy group of *arachnidean workers.
1854. Bushnan, in Orr’s Circ. Sc., Org. Nat., I. 77. The Pulmonary *Arachnidians, of which the true spiders and the scorpion are examples.
1877. Huxley, Anat. Inv. Anim., vii. 381. The six prominent *arachnidial mammillæ. Ibid., vii. 380. One of the most characteristic organs … is the *arachnidium, or apparatus by which the fine silky threads which constitute the web are produced.
1875. Encycl. Brit. (ed. 9), II. 273. The higher, at least, of the *arachnidous orders.
