ORDEE OF AMPHIBIA. 99 



products ("hey furnish (oil, fur, leather, ivory) are great induce- 

 ments for expeditions to be fitted out for their capture. 



The Amphibia do not inhabit intertropical regions, and they 

 increase more and more in number in proportion as one advances 

 towards the poles. They are found on the coasts of Europe — in 

 the North Seas, the British Channel, the Mediterranean ; in 

 the Black Sea they are abundant. Known to the Greeks and 

 Romans, the Amphibia gave rise to the stories about Tritons and 

 Nereids. 



The Amphibia comprise but two families : that of the Morse or 

 "Walrus, and that of the Seal. 



The Morse Family, Trichcekidip. — The only species of this 

 family is the Morse or Walrus, commonly called Sea-horse, or 

 Sea-cow, Trichechnu romiarus (Fig. 24). This animal measures 

 from 3J metres to 4 metres in length, by 3 metres in circum- 

 ference ; the assertions of travellers, who pretend to have seen 

 them of from 6 to 7 metres, must be regarded as exaggerations. 

 The Morse is covered with short scanty hair of a dark reddish 

 colour ; its muzzle is large and puffed out at the upper part, 

 and is terminated in a snout, in which are the nostrils, which are 

 turned upwards. Altogether, it is a creature of a massive and 

 unwieldjr appearance. 



The Morse is characterized by two powerful canine teeth, which, 

 descending vertically from its upper jaw, project somewhat out- 

 wards, and constitute formidable weapons. These tusks attain to as 

 many as 65 centimetres in length, and to a proportionate breadth. 

 The fidl- grown Morse has no incisive nor canine teeth on the 

 under jaw ; but when they are young they have two small incisive 

 teeth. The molar teeth, to the number of eight in each jaw, are 

 suited for crushing and grinding hard substances, and act in the 

 same way in which a pestle does on a mortar. 



The Morse inhabits exclusively the arctic polar regions : it is 

 especially common in the neighbourhood of Spitzbergen, of Nova 

 Zembla, and on the coasts of Siberia. It disports itself with ease 

 in the water, feeding on shelled MoUusks (especially of the genus 

 Mj/a), which it detaches from the submerged soil by means of its 

 tusks, which act like garden rakes. [Its gullet is too small to swaUow 

 a fish larger than a Herring, and it is now certain that this animal 



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