SEALS AND WHALES OF THE BRLTLSH SEAS. 85 



ODONTOCETI (TOOTHED WHALES). 



PHYSETERIDAI. 



The second sub-order into which tlie Cetacea are divided, is the 

 Odontoccti, or Toothed Wliales. In this section, baleen is never present, but 

 well-developed teeth are found in one or both jaws of the adult; in some 

 species they are very numerous ; sometimes, though rarely, deciduous. The 

 blow-hole is single, and the skull generally asymmetrical, or not precisely 

 alike on both sides of the medial line. Professor Flower divides the 

 Odontoccti into three families, one of which, the I'latanistida:, as already said, 

 is found only in India and South America : the other two, Pliysetciida; 

 and DclpliinidcB, arc represented in our Fauna by about fifteen species. 



Of the Pliysctcrida:, four genera are represented in the British fauna 

 by four or five species ; namely, one Physctcr, the Sperm Whale ; two 

 Hyperoodons, the common Beaked Whale, and a doubtful species called the 

 Broad-fronted Beaked Whale ; one Ziphiiis, Cuvier's Whale ; and one 

 Mesoplodon, Sowerby's Whale. 



SPERI\I WHALE, OR CACIIELOT. 



By far the most conspicuous species of this interesting group is the SperM 

 Whale, Physctcr inacroccpliahis (Linnaeus), A\hich rivals the Right-Whale in 

 commercial importance, and in the value of its products. This species has a 



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