U'KA. 



nt form niiy part <>t" the MI to which my attention was originally 



I diil nut contemplate iin t>f their nature. Hut as 



i.ire lor r\tm-i\e field.- of eiii|iiiry of long diinit inn to be cunflned 

 within the bounds pre*cril>ed by any one to himself, act-Mental circiiin- 

 I'-OB may brinj: important sulijcets nink-r review. 



Tin 1 .i few living shells, therefore, are represented | : 



which i- certainly the only suitable method of offering the. Teetaoea to 

 notice. Sune of the examples an- of great r.irity, and dillicult to be ob- 

 d, especially when entire and vigorous. 



1 Ime ii'it attempted to ki-ep any order here, then-fore this portion 

 of the work consists solely of miscellaneous obsenation-. They are 

 merely notes, accompanying accurate delineations of living specimens. 

 The deMiltnn form wherein what is said appears in this Volume entitle- 

 it to no higher consideration thun so many tnui-ient notes. 



rtheless, I feel conlident that some utility will be derived from 

 the iniality of the figures. The authors who professedly treat of Coucho 

 logy, even the most experienced, are hardly yet agreed on the precise 

 position and arrangement of shells. Probably the subjects of their diffe- 

 rence will ultimately prove trifling : Possibly too much weight is given 

 to minnti:e. It cannot be too often repeated, that the distinction of 

 animals and their part* should be very decided. Strongly marked, infi- 

 nite resemblances are general ; yet, on descending to the minutest fea- 

 tures, what two animals agree ? If two leaves from the same tree never 

 correspond, how can it be expected, amidst the variety of energies stimu- 

 lating the increment of living matter, that all the parts of two different 

 animals, such as may be visible or invisible to human sense, shall corre- 

 spond in nmnilius, 00 great is the difference among the fingers of many 

 persons, that we could hardly credit they belong to the hands of the 

 individual ; and sometimes there is no likeness whatsoever between the 



Differences of miinal should be therefore very strongly imprinted ; 

 and when they are so imprinted, they may be chosen for prominent 

 features in distinguishing the genera and .-pecies which occupy the world. 



Neglect of this has undoubtedly led to considerable confusion in th<- 



