1883.] on Whales^ Past and Present, and their Prohahle Origin. 15 



other organic structures known, past or present. Instead of living in 

 an age of degeneracy of physical growth, we are in an a^c of giants, 

 but it may beat the end of that age. For countless centuries impulses 

 from within and the forces of circumstances from without have been 

 gradually shaping the whales into their present wonderful form and 

 gigantic size, but the very perfection of their structure and their 

 magnitude combined, the rich supply of oil protecting their internal 

 parts from cold, the beautiful apparatus of whalebone by which their 

 nutrition is provided for, have been fatal gifts, which, under the 

 sudden revolution produced on the surface of the globe by the de- 

 velopment of the wants and arts of civilised man, cannot but lead in a 

 few years to their extinction. 



It does not need much foresight to divine the future history of 

 whales, but let us return to the question with which we started, 

 What was their probable origin ? 



In the first place, the evidence is absolutely conclusive that they 

 were not originally aquatic in habit, but are derived from terrestrial 

 mammals of fairly high organisation, belonging to the placental divi- 

 sion of the class, — animals in which a hairy covering was developed, 

 and with sense organs, especially that of smell, adapted for living on 

 land; animals, moreover, with four completely-developed pairs of 

 limbs on the type of the higher vertebrata, and not of that of fishes. 

 Although their teeth are now of the simple homodont and diphyodont 

 type, there is much evidence to show that this has taken place by the 

 process of degradation from a more perfect type, even the foetal teeth 

 of whalebone whales showing signs of differentiation into molars and 

 incisors, and many extinct forms, not only the Zeuglodons, but also 

 true dolphins, as the Squalodons, having a distinct heterodoni den- 

 tition, the loss of which, though technically called a " degradation," 

 has been a change in conformity to the habits and needs of the 

 individuals. So much may be considered very nearly, if not quite, 

 within the range of demonstrated facts, but it is in determining the 

 particular group of mammals from which the Cetacea arose that 

 greater difficulties are met with. 



One of the methods by which a land mammal may have been 

 changed into an aquatic one is clearly shown in the stages which still 

 survive among the Carnivora. The seals are obviously modifications 

 of the land Carnivora, the Otariae, or sea-lions and sea-bears, being 

 curiously intermediate. Many naturalists have been tempted to think 

 that the whales represent a still further stage of the same kind of 

 modification. So firmly has this idea taken root that in most popular 

 works on zoology in which an attempt has been made to trace the 

 pedigree of existing mammals, the Cetacea are definitely placed as 

 offshoots of the Pinnipedia, which in their turn are derived from the 

 Carnivora. But there is to my mind a fatal objection to this view. 

 The seal of course has much in common with the whale, inasmuch as 

 it is a mammal adapted for an aquatic life, but it Las been con- 

 verted to its general fish-like form by the peculiar development of its 



