The divergent apposition of the eyes in some of the Cetacea, particularly the larger species, suggests a lack of stereopsis or three-dimensional vision in these animals. The problem is posed by the inability to use both eyes simultaneously to view the same object with a degree of disparity measurable by the brain. This study examines the eyes of these animals, most notably the right whale (Eubalaena glacialis), and proposes a theory of monocular stereopsis attainable by the ability of one eye to create two pupils in the presence of a large biconvex lens, consequently displaying two images on one retina to be utilized for stereo-visual assessment by the brain.