EXTINCT ANIMALS 



are a great number of different kinds, some as 

 big as five feet in diameter. When cut across 

 they are seen to be divided into a number of 

 chambers internally. In fact, their structure is 

 the same as that of the beautiful shells of the 

 Pearly Nautilus (Fig. 193a), which to-day fives 

 in the Indian and Pacific oceans. The chambers 

 in the shell of the pearly nautilus contain gas 



Fig. 194. — The divided shell of the Pearly Na\itilus, with the 

 animal in place in the large front chamber. (Lent by the 

 Trustees of the British Museum.) 



and act as a float, whilst the animal lives in the 

 last chamber (Fig. 194). There are only some 

 three or four species of pearly nautilus now 

 living, and they represent a vast variety of 

 extinct creatures which comprise not only the 

 Ammonites but the more ancient Goniatites. 

 Some of these extinct allies of nautilus, such as 



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