NASSA. 21 



and even cancellated examples. Again, instead of there being a 

 uniform thickness observable, one set will be almost transparent, 

 or thin and hyaline, and another thick and. quite opaque. The 

 sculpturing is in many cases confined to the upper whorls, but 

 we find shells in which the pattern is commenced on the top, 

 gradually spreading in successive development until it covers 

 the whole shell; in one case it may form smooth unsculptured 

 ribs, or in another it may diverge into any of the forms of 

 sculpture we meet with in other groups of shells. The tip of 

 the spire may be of the same color as the remaining portion of the 

 shell, or it may vary into almost every shade of pink, rufous, 

 brown, purple, or almost black. 



" From these observations taken from the shells, and not 

 intended 'to support or illustrate any theory, it is very easy to 

 see that instead of a fixedness in the characters used for the 

 determination of species, exactly the opposite appears to be the 

 case; the specimens presenting such an amount of variation in 

 every direction that it becomes absolutely impossible to atlix 

 any set of characters to them that will lead to their future 

 recognition. 



" The greater part of the shells figured and described as new 

 species have for their recommendation to our notice a single 

 specimen, and that often in bad condition. Men are so anxious 

 to have their names appended to something new that every other 

 consideration is overlooked by them. They cannot wait until 

 sufficient evidence is produced either to confirm their opinions 

 or show them that the characters they had given were incorrect, 

 but down it goes on to paper, and there it remains." 



What a commentary on this and preceding paragraphs is the 

 printing of numerous new names and descriptions in the very 

 pamphlet from which these brave extracts are made! These 

 new species, alas ! are not even figured, no dimensions are given, 

 and in many cases no locality. The descriptions are prefaced 

 by the remark " What are the shells described in the following 

 pages ? My answer is, I do not know. The amount of knowl- 

 edge is confined to the single specimens (!) in most instances 

 and to three or four at most in any case. At present these 

 shells appear to me to be distinct, simply because of my igno- 

 rance of all their alliances, but that this should be the real 



