GASTEROPODES. 325 



having dissolved in a week, liberated multitudes of their inmates, nar- 

 rowly resembling all those I had seen before. 



These animals were equally restless during confinement as after libera- 

 tion. Their constant change of place and position rendered all compu- 

 tation of their numbers liable to fallacy, likewise, if appearing larger when 

 confined than free, this may have resulted from some optical illusion, 

 such as the convexity of the fluid contents of the capsules. 



It is evident, however, that a single capsule is sometimes occupied 

 as a common prison by a number of Nautilines, all confined in a common 

 integument. Likewise, that the young animal is sometimes contained 

 within its own peculiar ovum, from which it is to be liberated on attain- 

 ing maturity. 



Although I have made very numerous observations on the Nauti- 

 lines, I regret to say that they appear so vague and indefinite to myself, 

 that I cannot feel they will prove satisfactory to others. 



Their presence under such a variety of circumstances infers a pecu- 

 liarity which ought to receive farther investigation. 



Apparently the Nautiline is the progeny of the Doris. Nevertheless 

 I do not presume to identify the two, so long as observation and experi- 

 ment are wanting to prove the fact. 



Many minute specimens of many species of the former have fallen 

 into my possession, yet I never beheld any so minute that a thousand 

 would not be required of the Nautiline to equal its size. 



Nothing has hitherto indicated the slightest approach to metamor- 

 phosis. No incident whatever has attended the existence of the Nauti- 

 line, excepting its death in the shell, proving the transient life of the one, 

 and the permanent substance of the other. 



If such a metamorphosis succeeds, as we are induced to believe, 

 there are indispensable conditions necessary in food, in temperature, a 

 marine abode, and the like, for which there is no suitable substitute in 

 confinement. 



Without affirming that the tenant of the shell of the Nautiline is 

 allied to Animalcula infusoria, it would be gratifying to see the result 



