the Inhabitant of the Argonaut. 397 



solution of this question, yet he has presented a new argu- 

 ment in favour of the parasitic nature of the Ocythoe. It 

 consists in this : — All conchologists know that in the testa- 

 ceous Mollusca the shell of the young animal, when it is still 

 contained in the egg, frequently differs greatly from the shell 

 in the adult state, and of which it forms the nucleus. Now, 

 Mr. Gray has remarked that, in the shell of the Argonaut, 

 the nucleus, which is very different in shape from the shell, 

 properly so called, is nearly 4 lines in diameter, and, conse- 

 quently, is many times larger than the largest eggs which 

 have been found in the shell of the Argonaut; whence he con- 

 cludes, and with much reason, that the true animal of the Ar- 

 gonaut is, when hatched, much larger than, and consequently 

 very different from, these young Molluscs ; and that this 

 latter cannot, therefore, have been the true constructor of the 

 shell which it inhabits ; it not being possible that its nucleus 

 (supposing, with Poli, that it is provided with it while in the 

 egg state) should be many times larger than the egg* Be- 

 sides which, Mr. Gray confirms, by reiterated observations, 

 that in all the conchyliferous Mollusca the shell is developed 

 in the egg, and even before the developement of the other 

 organs ; and he opposes the argument drawn from the apparent 

 absence of muscular impression, by the example of that of the 

 Carinaria, in which nothing more is visible than in the Argo- 

 naut, and which yet evidently adheres to the animal during 

 its life. 



It was under these circumstances, communicated to him by 

 Mrs. Power, that M. Rang, an officer in the Royal Marines, 

 who has for some time devoted himself to the study of mala- 

 cology, and is fully acquainted with the state of this question, 

 made the observations which he has addressed to the Academy. 

 Placed as a Port-Captain at Algiers, he has had frequent op- 

 portunities of seeing the Octopod of the Argonaut, both 

 swimming on the open sea, and walking at the bottom of the 

 water : he has even been able to put some of them alive into a 

 tub of sea-water, and thus to observe them more at his leisure. 



Being acquainted with Mrs. Power's first experiments, the 

 details of which had been furnished him by that lady, he was 

 eager to repeat them. He therefore removed some pieces of 

 the shell from a living specimen (unfortunately, he does not 

 say from what part they were taken) ; and he perceived that, 

 at the end of six days, the breach made in the shell was com- 

 pletely closed up, and so repaired ; " but," he adds, " in 

 truth, notwithstanding our inclination to consider the Cepha- 



* Mr. Gray has since withdrawn this argument, in a communication to 

 this Magazine. (See p. 217. of the present Volume) — Ed. 



G G 3 



