CHAPTER VIII. 

 THE TOOTHED WHALES OR ODONTOCETI 



THIS group contains by far the larger number of 

 whales. It embraces all the dolphins, Sperm 

 whales, beaked whales, etc. It contrasts markedly 

 with the Mystacoceti, the differences being so great 

 that more than one naturalist, as already said, is dis- 

 posed to give to the two a different line of descent. 

 The most characteristic feature of the Oclontoceti, 

 and the one which has given to it its name, is the 

 possession of functional teeth. These are never 

 totally absent in any member of this group, though 

 they may be as in the Narwhal among the true 

 dolphins, and in the Ziphioid whales greatly reduced 

 in number. Correlated with the presence of teeth 

 is the absence of baleen. The skull is always more 

 or less asymmetrical, and this asymmetry is often 

 greatly exaggerated, especially in the Sperm whales. 

 The maxillae overlap the frontal bones. The nasals 

 share in the asymmetry of the skull, and one only 

 is sometimes developed. In connection with this the 

 single* blow hole, either median in position, or (Sperm 



* It is said to be double in Kogia pottsi, but the left spiracle is ten 



172 



times larger. 



