354 FOLLOW THE WHALE 



thousands of specimens of no fewer than two dozen quite different 

 genera of Cetotheres have now been unearthed, and it is plain that, 

 although they are indeed very primitive, they are still distinctly 

 Baleen Whales, or Mysticeti. They lasted about twenty-two million 

 years, and then died out suddenly. They appeared just as suddenly 

 and apparently from nowhere. Like all other groups of whales, they 

 must have evolved somewhere where no deposits were laid down — 

 either in the real oceans or in lakes and rivers. A third group of 

 whales that are found in the Miocene rocks are equivalent in stand- 

 ing^ to the Cetotheres among the Mysticeti, but they are Toothed 

 Whales, or Odontoceti. These are the Squalodontidae. 



The Squalodonts were even more peculiar. They were a dying 

 race during the Miocene, and they retained some altogether un- 

 whalelike characters. Their skulls were typically cetacean and not 

 unlike those of some dolphins, but their teeth were sixty in number 

 and were clearly divided into twelve simple, peglike front teeth, or 

 incisors, four recurved eyeteeth, or canines, sixteen holding teeth, or 

 premolars, with double roots, and twenty-eight triangular, triple- 

 rooted grinding teeth, or molars, with one serrated upper edge. This 

 is the division of teeth found in the average land mammal, but at 

 the same time it displays the multiplication of premolars and molars 

 that is typically whaleUke and which, in its ultimate form, gives rise 

 to the tremendous, continuous rows of teeth, all alike, that are seen 

 in certain whales today. The Squalodonts are placed among the 

 Odontoceti, or Toothed Whales, but they form a sort of missing 

 link between them and an entirely different major group of whales, 

 which also became extinct in the Miocene, called the Zeuglodonts. 



Now, these animals are so unlike any whales living today, either 

 Odontoceti or Mysticeti, that they have been placed in a separate 

 suborder called the Archaeoceti, or the "First Whales." In their day 

 they were very common creatures and their remains have been found 

 in considerable quantities in North and South America, in western 

 Europe, the Caucasus, New Zealand, and Australia. Some grew to a 

 length of seventy feet. Their skulls, though obviously cetacean, are 

 still more like those of other mammals. They had normal nasal bones 

 and their nostrils were in the ordinary mammalian position at the tip 

 of the snout and were probably not blowholes in the technical sense. 

 Their neck vertebrae were long and joined like those of seals so that 



