SHELL OF THE NAUTILUS. 171 



Surgeons, whose authority is of the highest value. 

 Again^ it was found by Madame Power, (and the fact 

 has been subsequently corroborated,) that the shell of the 

 argonaut while investing the living animal, is not hard as 

 we see it in cabinets ; but soft, yielding, and flexible, with 

 a decree of elasticity sufficient for the respiratory func- 

 tions, and the degree of locomotion required by its 

 inhabitant; it is also permeable to light. It was also 

 proved, that the embryo of the argonaut, while yet in 

 the egg, and at an advanced stage of development, had 

 neither membraneous arms nor shell ; but that both 

 became developed, in a given time, namely, ten or 

 twelve days after exclusion. It was further discovered, 

 that the cephalopod of this shell possessed the power of 

 repairing it when fractured, or when portions were re- 

 moved for the purpose of experiment, and with the same 

 matter as that of which the rest of the shell consists. 

 It was still further proved, contrary to the assertions of 

 some naturalists, that the shell is moulded on the body 

 of the animal, to the form of which it is beautifully 

 adapted ; and that in every instance the animal maintains 

 the same relative position in its shell. Again, contrary 

 to the statements of M. Blainville and others, it was found 

 that the result of depriving the cephalopod of the argonuat 

 of its shell, is an immediate loss of vital power, and 



