40 



male Argonaut possessed neither a shell nor the organs for secreting 

 it, this fact would not render the hypothesis of the parasitism of the 

 female, which does possess the calcifying membranes, at all the less 

 tenable." 



With respect to the shell of the Argonaut, Professor Owen ob- 

 served, that " any argument founded on observations on the dried 

 shells in cabinets, could tend only to mislead the observer. Madame 

 Power's specimens having been recently collected, and preserved in 

 alcohol of not too great strength, manifested much of the original 

 transparency and elasticity of the living shell. It was obvious, 

 tlierefor^, that light would act in developing the coloured spots on 

 the contained body of the Argonaut ; and this fact is important in 

 reference to the seventh argument in M. de Blainville's memoir of 

 1837, p. 4., in which he asserts that ' those parts of mollusks which 

 are covered with a shell are constantly white or colourless, but the 

 mantle investing the body of the Argonaut is highly coloured.' Now, 

 if j\I. de Blainville's object had been to prove that the Ocythoe did 

 not inhabit a shell at all, the force or purport of this observation 

 would have been intelligible ; but the question is not whether the 

 body of the Ocythoe is or is not covered with a shell, but whether 

 it makes or steals that shell. But perhaps the argument, founded 

 on the supposed opacity of the Argonaut shell, was brought forward 

 merely to prove, that up to a certain period of its existence the Ocy- 

 thoe was naked, and that the Argonaut-shell was taken possess<|jfc 

 of only for some temporary purpose, as for ovi])osition. 'I'he obser- 

 vations, however.which I published in 1836 (Cyclop, of Anat., Art. 

 Cephalopoda, p. 544), proved that the young Cephalopod of the 

 Argonaut was provided with a shell prior to the pei'iod of oviposi- 

 tion, and tliat tlie body entirely filled the shell at that period. The 

 present collection still more satisfactorily establishes the fact, that 

 the Argonaut- shell is not assumed by the Cephalopod for a tempo- 

 rary purpose : for the shell which protects the j^oung would be wholly 

 inadequate as a nidus for the ova of the mature animal ; and for wTiat 

 purpose, then, on the parasitic theory, is the shell assumed by the 

 Cephalopod before its ovarium has received the stimulus of sexual 

 development }" 



In Madame Power's recently-collected specimens, the shell, after 

 a few hours' soaking in water, regained so much of its original 

 flexibility as to demonstrate its ])ower of varying its form with the 

 varying bulk arising from the respiratory and locomotive actions of 

 the inhabitant*. 



The inductions, therefore, which the present collection of Argo- 

 nauts of different ages and sizes legitimately sustained, were in exact 



* In M. de Blainville's Letter on the Parasitism of the Argonaut (1837), 

 the follovving assertion is offered as the tenth argument : " La mode de 

 locomotion et de respiration de ces animaux par la contraction et la dilatr- 

 tion alternatives du sac, ne permet pas d'admettre qu' il y ait adherence 

 de la peau avec la coq'jille, k moins que de supposer que celle-ci soit flexi- 

 ble et elastique, et suive tous les raouvemens de celle-la, ce qui est bien 

 loin de la v6rite." 



