the arrangement of similar parts of an organism around its transverse axis or along the axis of a particular organ. Such parts as the rays of fins, digits, feathers, and flower petals were called homonomous or parameral by the German biologist E. Haeckel. Also thus designated are the homogenous body segments of arthropod animals. (Heterogenous segments are called heteronomous.) Homonomy is a particular case of homology.