422 PHYSETERIDiE. 



on the group in the Transactions of the Zoological 

 Society, " lead to the belief that the existing Ziphioids 

 are the survivors of an ancient family which once played 

 a far more important part than now among the Cetacean 

 inhabitants of the ocean, but which have been gradually 

 replaced by other forms, and are themselves probably 

 destined ere long to share the fate of their once numerous 

 allies or progenitors/^ They are at once distinguished 

 from other toothed Whales, by many important structural 

 differences both external and internal. In the upper jaw 

 there are no functional teeth, which are only occasionally 

 represented by rudiments, which never cut the gums, 

 while those of the lower jaw are reduced to either one or 

 two pairs, wliich are often greatly developed but sometimes 

 remain almost rudimentary. The snout is produced into 

 a more or less distinctly marked " beak," the flippers are 

 short and rounded and the dorsal-fin placed very far 

 back. The blow-hole is crescentic, and two diverging 

 furrows in the skin of the throat assume the form of the 

 letter V with its angle directed forward. The family has 

 been separated into an enormous number of genera, only 

 four of which are recognized in Prof. Flower's paper. 

 Of these the first and best marked is Hyperoodon, charac- 

 terized by great bony crests which rise from the upper 

 surface of the maxillary bones of the skull, by the rudi- 

 mentary condition of the only pair of teeth which it 

 possesses, and by the small hard horny tubercles which 

 cover its palate. 



The Common Beaked-Whale or " Bottle-head," as it is 

 usually called, is by far the best known species of the 

 family. It is a native of the North Atlantic Ocean, and 

 goes as far north as Greenland in summer. In autumn 

 it constantly comes into British waters, and specimens are 

 killed almost every year on some part of our coast. One 



