a. and sb. Zool. [f. mod.L. Xiphosūra pl. (irreg. f. Gr. ξίφος sword + οὐρά tail, instead of the correct form Xiphūra) + -AN.] a. adj. Belonging to the order Xiphosura of Arachnida, including the king-crab (Limulus) with a long sharp telson, and the extinct genus Belinurus. b. sb. An arachnid of this order, So Xiphosure (= b); Xiphosurous, Xiphurous adjs. (= a).
1837. Penny Cycl., IX. 460/1. Latreille … admitted into the class Crustacea 12 orders, viz., the Decapods,… the Xyphosures [sic], and the Siphonostomes.
1879. H. A. Nicholson, Palæont. (ed. 2), I. xviii. 385. In the Devonian no certain traces of Xiphosurans have yet been detected, but several types occur in the Carboniferous.
1888. Rolleston & Jackson, Anim. Life, 528. A Xiphosuran is found in the upper Silurian.
