OBSERVATIONS ON THE ARGONAUT. 151 



On the 24th returned to examine the same shell, and there 

 found the little mollusc already covered by its thin shell, 

 which was 3j lines long. The mollusc was completely form- 

 ed, and its shell had the form of the spire in which it had 

 been framed. 



All the experiments made by me on this head have always 

 had the same results ; from which I have deduced that the 

 mollusc when born, is naked and incomplete at the time of 

 exclusion from the egg ; that it becomes progressively deve- 

 loped in the end of the spire of the parent argonaut; and 

 that after a given time it goes on forming its shell. 



As far as I have been able to make out, not more than two 

 or three eggs develope themselves at the same time; and 

 when the young have grown to the length of 9 lines, they suc- 

 cessively inclose themselves in the spiral of the parent shell, 

 where the other seven arms are thrown out in the manner of 

 buds. The young poulp takes three days to arrive at the 

 length of 9 lines ; and four in the spiral to develope itself. — 

 The parent retains it three days more under her, and then 

 throws it forth from the shell. 



I attempted to produce the developement of the eggs as far 

 as the production of the young poulp, without the aid of the 

 mother, by suspending them in a fine linen bag in a phial of 

 sea water, taking care to change it three times a day ; but 

 this attempt did not succeed, having no other result than the 

 swelling of the eggs, and this alone from their beginning to 

 putrify. 



I have concluded from this that the glutinous material in 

 which they are enveloped in the spire of the parent con- 

 duces to their developement; and this material being evi- 

 dently a secretion of the parent, it may be said that without 

 her aid the eggs could not be developed, and the young shell 

 could not have its foundation laid in the end of the spire. 



In spite of all these successful experiments in favour of the 

 shell being the property of the poulp of the argonaut, I wish- 

 ed to assure myself of it in a manner never yet attempted by 

 others. " If the argonaut " I said " be the constructor of its 

 shell, it should be able to repair the damage in case of frac- 

 ture." Although Signor Ranzani had said, " It is not to be 

 believed that these poulps of the argonaut should be so ill 

 provided with means wherewith to preserve their existence, 

 that if the first habitation be broken or lost, they cannot con- 

 struct another." Still I thought from his manner of express- 

 ing himself, it was very evident that he had never made ex- 

 periments to this end. Moreover, I, who have experimented 

 on a hundred of these molluscs, have found that having lost 



