Species with large eggs and substantial yolk typically have superficial cleavage that may be complete, equal, unequal, or
meroblastic (Gemmill, 1920; Nyholm, 1949; Uchida and Yamada, 1968; Mergner, 1971; Chia and Spaulding, 1972; Campbell, 1974; Spaulding, 1974; Fautin et al., 1989).