46 



nauta hians, Solander, or Ocytho'e Cranchii, Leech) was adhering! 

 ■with the vela retracted, to the side of the vessel of sea- water in which 

 it was placed, the shell could be removed' : in other words, there 

 was no muscular adhesion. ' In this state of captivity some of the 

 Cephalopods lost the power of retaining hold of the shell ; one which 

 had thus left its shell lived several hours, and showed no desire to 

 return.' 



" Now had the Ocythoe been a parasite ; — supposing that it had ever 

 before obtained its shell by placing its body in one ready-made ; — and 

 had it been in the habit of repeating this act during its whole period 

 of growth, as it must have done to produce the concordance in size 

 which the observations of Poll, Prevost, Madame Power, and myself 

 establish as a general fact ; — then the probability ^would have been 

 greater that the Cephalopod would have returned to, and so man- 

 oeuvred as to regain possession of, its shell : the observation of 

 such a fact would have told as strongly for the parasitic theory as 

 tlie phsenomena witnessed by Mr. Cranch testify in my opinion 

 against it. I have repeated Mr. Cranch's experiment with a true 

 parasite, — the common Hermit-crab of our coasts ; and I would in- 

 vite any naturalist to remove a parasitic Pagurus from its shell, and 

 place it with the empty shell in a basin of sea-water, and see whe- 

 ther the parasite will manifest no desire to return his body into its 

 accustomed hiding-place. In my experiments the Pagurus lost no 

 time in regaining possession of its shell. As Mr. Cranch's Argonaut 

 survived four hours without showing the least disposition to return 

 to its shell, instead of concluding therefrom that it had stolen it, I 

 infer that such a mode of acquiring a shell was totally foreign to 

 its instincts and oeconomy. 



" Mad. Power states that the constant result of depriving the Argo- 

 naut of its shell is a gradual loss of vital power and ultimate death 

 within a few hours at furthest. The experiment of M. Sander 

 Rang was followed by the same result. 



" With respect to the eighth statement, I must say that the 

 weakness of the side of the question advocated by M. de Blainville 

 is clearly betrayed by the dubious notice of the Ocythoe by M. Ra- 

 finesque having been pressed into the service of the parasitic theorj' 

 in the disguise of an established fact. M. Rang* informs us that 

 the entire description of the much tallied-of Ocythoe, as given by 

 its discoverer, is as follows : ' Appendices tentaculaires au nombre 

 de huit, les deux superieures ailes interieurement, a sugoirs inte- 

 rieurs, pedoncules, reunis par I'aile laterale, sans aucune mem- 

 brane a leur base' ; and amongst other just obsei-vations on the 

 inadequacy of this meagre indication, to the support of the theory 

 that the Cephalopod of the Argonaut naturally existed without its 

 shell, and was identical with the Ocythoe of Rafinesque, M. Rang 

 adds that the description of the Ocythoe above cited is equally ap- 

 plicable to any of the species of Octopus, to which M. Ferussac 

 had applied the term ' Veli/eres.' 



* Giierin's Magazine, p. 31. 



