122 



bearings with the relations of othcr Molbiscans and their shells, he 

 ■was more and more inclined to believe that the animal found in the 

 shell of Argonautą was a parasite. He gavę the following reasons 

 for this belief. 



"1. The animal hasnone of thosepeculiaritiesof organizationfor the 

 deposition, formation, and growth of the shell, nor even the museles 

 for attaching it to the shell, ■vvhich are found in all other shell- 

 bearing MoUuscans ; instead of vvhich it agrees in form, colour, and 

 structure \vith the naked Mollusca, especially the naked Cephalo- 

 pods. 



" 2. Tlie shell, although it agrees in everyrespect ^ith the shells 

 of other MoUuscans in structure, formation, and growth, is evidently 

 not moulded on the body of the animal usually found in it, as other 

 shells are ; but exactly agrees in every point (except in the form of 

 the spire), with the shell of Carinaria, which coincided with the other 

 MoUuscans in all these respects. 



"3. The body of the animal does not appear to have the po\ver of 

 secreting calcareous matter, for it does not, likę all the MoUusca 

 which have that power, secrete either a solid deposit or distinct septa 

 to adapt the cavity of the shell to the increase of the bod}^ nor does 

 it cover over \vith calcareous matter any sand or other extraneous 

 bodies which may have accidentally intruded themselves between the 

 mantle and the shell, butleaves the sand, which is often found mixed 

 -vvith the eggs, free, without taking any means to prevent it from 

 irritating the sldn. 



" 4. The young shell of the just hatched animal which forms 

 the apex of the shell at all periods of its grovi'th, is much larger 

 (ten times) than the eggs contained in the upper part of the cavity of 

 the Argonaut. 



Mr. Gray further stated, thathe does not think that any inference 

 can be drawn in favour of the opinion that the Ocythoe forms the 

 sheU, from either of the three arguments -vvhich have been produced 

 in favour of that hypothesis, \vhich he then examined in detail. 



" 5. He believes that Poli mušt have been misled when he thought 

 that he had discovered the animal in the egg of an Ocythoe covered 

 •u'ith the " rudiment of a shell," because all the MoUuscans which 

 he has seen in the egg (Cephalopods as ■u'ell as others) \vere covered 

 ■vvith a well-develoi)ed shell, even before all the organs were deve- 

 loped, and the figure which Poli gives of the rudiment does not 

 agree \vith the nucleus found on the apex of the shell of the Argo- 

 nauts. Unfortunately, none of the eggs of the Ocytho'ės tliat have 

 been examined by other observers have been enough developed to 

 show the fojtal animal. 



" 6. The difFerent species of Argonautą are said to be inhabited by 

 different species of Ocythoe; but allo\ving this to be the case, it 

 only proves that each of these genera have local species : the šame 

 may be observed -vvith respect to the Hermit Crabs, -vvithout proving 

 anything in favour of their being the framers of the shell they live 

 in. 



" 7. That though some specimens of Ocythoe preserved in their 



