OKDEK OF AMPHIBIA. 
99 
products they 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, Trichechidce . — The only species of this 
family is the Morse or Walrus, commonly called Sea-horse, or 
Sea-cow, Trichechus rosmarus (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 
unwieldy 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 full-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 Mollusks (especially of the genus 
My a), which it detaches from the submerged soil by means of its 
tusks, which act like garden rakes. [Its gullet is too small to swallow 
a fish larger than a Herring, and it is now certain that this animal 
h 2 
