ORDER CETACEA • DICTIONARY ONE.COM • Definition of Order Cetacea

... like an otter and a seal should be carried further, it will inevitably lead to forms possessing characters such as those displayed by whales and the related porpoises, dolphins, and narwhals of the order cetacea. In their make-up all of these animals clearly possess the general characteristics of mammals, and they constitute collectively another limb which has sprung from the same stock as the carnivora, although at an earlier time. This we believe because ...

— The Doctrine of Evolution - Its Basis and Its Scope • Henry Edward Crampton