CHAPTER XII. 

 ZEUGLODONTS AND THEIR ALLIES 



FAMILY, SQUALODONTIDAE 



THIS family, consisting entirely of extinct forms, 

 may be thus defined : 



Teeth in both jaws specialised into incisors, canines, 

 pre-molars, and molars. Skull, dolphin-like. 



These whales, whose remains are known from the 

 Miocene and Pliocene of Europe, America, and 

 Australia, form a connecting link between the Zeuglo- 

 donts (with which group they have been united) and 

 the modern Odontocetes. Like the Zeuglodonts the 

 teeth are specialised ; and, moreover, the molars have 

 a coarsely serrate cutting edge like the Zeuglodont 

 tooth, but the serrations are confined to one side. 

 The teeth too are more numerous, though some of 

 them are two-rooted as in Zeuglodon. 



The archaic characters of the Squalodontidae are 

 also shown by the fact that a number of the teeth 

 of the upper jaw are borne by the pre-maxilla. The 

 skull, however, apart from this feature, is not archaic, 

 and the rudimentary nasals of modern Cetaceans 

 have been acquired. In Prosqualodon, however, this 



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