Anat. and Zool. Pl. -a. Also (more correctly) xipho-. [mod. L., properly xiphoplastron, f. Gr. ξίφος sword + PLASTRON.] Each of the fourth or hindmost pair of lateral plates in the plastron of a turtle. Hence Xiphiplastral a., pertaining to or constituting a xiphiplastron; sb. a xiphiplastral plate, a xiphiplastron.
1871. Huxley, Anat. Vert., v. 202. In the Turtle the plastron consists of nine pieces … the fourth [lateral], xiphiplastron.
1889. Nicholson & Lydekker, Palæont., liii. II. 1084. [The pubis and the ischium] may be anchylosed to the xiphiplastral.
1889. Lydekker, in Q. Jrnl. Geol. Soc., 1 Aug., 511. The imperfect left xiphiplastral [of a Chelonian].
