geo malism (jeomalizm)

[ + -ism.] A tendency of an animal to react against the attraction of gravitation by equal growth in horizontal planes, so as to balance one side with another, and one lateral organ with another. Thus, the oyster and many other animals are when young normally bilateral; but subsequently, when they are turned over and attached by one side, the dorsum and venter, which were primarily unequal and held vertically, take the place of the right and left sides and a ume a horizontal posture. A. Hyatt, Proc. Amer. A oc. Adv. Sci., 1880, p. 541. Geo malism appears in its primitive aspect among the sponges, since they are comparatively soft and supported by a pliable and primitively fragmentary internal skeleton. Stand . Nat . Hist . , I. 50.