Development of the Cetacean Nasal Skull

Morphogeny of the nasal skull was investigated in 92 embryos of 13 species of Cetacea. Compared to the original nasal capsule of land mammals, the nasal structures of Cetacea show many weighty transformations. The morphogeny of the nasal skull suggests that all cetaceans are of common origin and form a single monophyletic order.