Dorsal ( Barclay, 1803 ) : Toward the back of the body, or away from the belly, in the transverse plane (Henle, 1855); the opposite of ventral (Schulze, 1893); introduced formally by Barclay (1803, pp. 120, 162), who paired it with sternal. At least by the second century Galen had indicated its use, for example, in describing a direction "back toward the dorsum"; see translation by May (1968, p. 701). In Aristotle's De Partibus Animalium, there is reference to "on their [univalves] dorsal surface they have a shell"; see translation by Ogle (1912; 679b, 23-24). Also see Brusca & Brusca (1990, p. 46).