GASTEROPODES. 321 
cannot speak with confidence of their true character. Some are dim or 
obscure from the interception of vapour, clouds, or films, lessening their 
distinctness to the eye. 
All bear a general resemblance to each other, without betraying the 
precise action of any single member. 
Thus it would be vain for us to reason on what they are, or what 
may be their use and purpose. The whole body is susceptible of some 
contraction within the shell, and of some protrusion beyond it. All are 
endowed with vigorous locomotion,—all contract, decay, and disappear, 
and leave incredible multitudes of whitened, spiral, wide-mouthed shells 
behind them. 
As regards these general facts there seems to be no illusion ; they 
are daily verified. 
The whole Nautilines contained in any mass of spawn are not pro- 
duced at once. It is evident that the requisite degree of maturity is 
progressively attained. The life of all is short, and having escaped from 
confinement, they speedily perish. 
It is extremely probable that, notwithstanding the preceding gene- 
ral conclusions regarding the reciprocal resemblances of these beings, and 
the form of their shells, many discrepancies and distinctions would be 
discovered by patient investigation. 
Through the medium of the Doris we have been rendered familiar 
with the Nautiline, but it does not appear that this minute being is by 
any means peculiar to the tribe. There is reason to conjecture that a 
similar animal is seen in an early stage of many others. 
Drawings of the different Nautilines have been very carefully exe- 
cuted, both as complete and of the shells only. But no great difference 
is to be recognized among them. Artists seldom coincide exactly in their 
representations of very minute objects. 
But it must be owned that these objects are not seen with sufficient 
plainness and distinctness. Thus, the few remarks to be made on the 
subject, are intended simply for the purpose of attracting attention. 
Let us remember what occurred with the Murew antiquus, one of our 
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