SPERM-WHALE. 273 



young, are annually captured by the Norwegian fishermen, who 

 drive them into narrow fjords, the entrances of which they 

 subsequently bar, ard there spear them to death. 



THE TOOTHED WHALES. FAMILY PHYSETERID^. 



The members of this and the remaining Families of the Order 

 are distinguished from the Balanidce by having no whale-bone 

 in the upper, and by the presence of teeth in the lower jaw at least, 

 although in some cases these may be reduced to a single pair. 

 In consequence of this and other important structural differ- 

 ences, the Balanida are regarded as constituting one sub- 

 order — the Mystacoceti — by themselves, while the whole of the 

 other existing Cetaceans collectively form a second sub-ordinal 

 group, termed the Odontoceti. In all the members of the latter 

 group, the upper surface of the skull is more or less a-sym- 

 metrical ; the nasal bones are in the form of mere nodules, and 

 never roof over the hinder portion of the nasal cavity in the 

 manner characterising the Whale-bone Whales ; while the 

 aperture of the nostrils is a single, more or less, crescent- like 

 slit. 



The members of the present Family are sufficiently chaiacter- 

 ised by the absence of functional teeth in the upper jaw ; and 

 by the hinder region of the skull being elevated in the form 

 of a high crest or ridge behind the aperture of the nostrils. 



THE SPERM-WHALES. GENUS PHYSETER. 



Physeter^ Linn., Syst. Nat. ed. 12, vol. i. p. 107 (1766). 



Head enormously large, and truncated in front, with the 

 upper surface of the skull forming a hollow pit, surrounded on 

 the sides and behind by a tall semi-circular wall of bone; 

 lower jaw long and narrow, with its two +)ranches united in 

 front for more than half their total length; from twenty to 



5 I 



