12 



habits the shell sketched in fig. 5. Aristotle wrote at first (Hist. 

 Anim. Lib. ix.) that " touching the growth of the shell nothing is as 

 yet exactly determined." Naturalists contended that the animal 

 itself was destitute of testaceous covering; that it was parasitic ; that 

 it made use of the Argonaut shell much in the same way as the 

 Hermit Crab of our shores occupies the first vacant Winkle which is 

 of convenient or suitable size. In confirmation of this theory was 

 adduced the fact that a Dr. Moffat caught in the Madras Eoads an 

 Octopus, which had its unprotected body firmly inserted in an Indian 

 Ghee-bowl, and that a M. Desjardins found another species comfort- 

 ably lodged in a Dolium shell. Moreover, it was affirmed that the 

 Argonaut had been seen quitting the shell, and moving about with- 

 out any protective covering, as though the absence of its house was 

 of small moment ; finally, that specimens procured in a living state 

 gave no sign of being affixed to the shell itself by any method of 

 muscular attachment. 



To a Madame Power is due the merit of clearing up in a great 

 measure these opinions ; that lady, in November 1836, described a 

 series of experiments made by her at Messina, which testified to the 

 Argonaut not being dependent for a home upon others' labours. 

 Madame Power, causing a number of small cages to be constructed, 

 enclosed in these the Argonauts, and sinking the cases in the sea, 

 examined from time to time the doings of the prisoners. It 

 was then discovered that the Cephalopod always met with in 

 the Argonaut shell, had the power of repairing 1 fractures in 

 its testaceous covering with similar testaceous material, that it 

 remedied these injuries by means of its so-called " sails " (fig. 

 5), that these sails were closely applied to the whole of the 

 sides of the shell (much more than in the woodcut, where the tentacle 

 is shrunk and somewhat distorted, from the action of the spirits in 

 which the specimen is preserved), that, as the Argonaut animal in- 

 creased in bulk, 2 so did the shell in magnitude, and that there was 



1 Several examples of self-repaired Argonaut shells can be seen in the Museum of 

 the College of Surgeons. 



2 In the same Museum are many specimens of the Paper Nautilus shell with the 

 Cephalopod inside, of various progressive sizes, commencing with one smaller than an 

 inch in diameter. 



