ARGONAUTA. NAUTILUS. 101 



CHAPTER XIL 



" So many families of the fourth order, Cepha- 

 hpoda, are found only in a fossil state, and which 

 you will not easily meet with, that I shall not con- 

 sider it needful to give you the whole catalogue," 

 observed Mr. Elliot to his young pupils at the 

 beginning of the next lesson. 



" But we are exceedingly interested about 

 fossils," replied Charles ; " pray do not pass any 

 species that we may be likely to find." 



" And I," said Lucy, " have much wished to 

 ask whether the snake-stone ever was a shell ? it 

 is something like a Planorbis, but heavy and im- 

 perfect." 



" I will answer your question presently,"' said 

 her father. *' Tell me what genera remain to be 

 noticed among the univalves of Linnaeus .^" 



" Argonauta and Nautilus,'''' was the ready 

 reply. 



" The animals inhabiting these shells are Ce- 

 phalopoda. The word indicates the position of 

 the feet, or more properly arms of the animal, 

 which are ranged round the head like a crown. 



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