Tebble name: Xylophaga praestans E A. Smith. Smith & Heppell name: Xylophaga praestans E A. Smith, 1903. To size: To 20mm. Shell Structure: Thin, brittle. Mesoplax large, sharply triangular in outline. Equivalve: Equivalve. Equilateral: Subequilateral, beaks almost at midline.