INTRODUCTION. ll 
their names appended to something new that every other consideration 
is overlooked by them. They cannot wait until sufficient evidence be 
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 itremains. It will not be very difficult to decipher 
what amount of time and trouble is expended over these christenings 
when we see such a shell as the N. fossata, Gould, one of the 
largest shells in this genus, and about which there has been more 
discussion than any other, re-named in 1868, N. Moreleti, Crosse, 
ten years after it had been raised from a species to a sub-genus by 
H. and A. Ad., under the title of Zaphon elegans, Reeve. 
In my list of affinities occurring amongst about twelve hundred 
varieties, the examples have been selected for the purpose of 
showing special peculiarities connecting shells said to form distinct 
species. All the more closely filling-in forms occurring between 
them have not been noticed. 
The common shells, such as the Nassa reticulata, Linn., incras- 
sata, Miill., with its variety glaberrima, Gmel., W&c., appear to 
radiate into the shells of every other group, like a star composed of 
many rays. 
We find these shells varying in form in every direction ; one 
shell will be tall and elongated, and the next lying beside it will be 
short and dumpy ; the body-whorl will be much longer than the 
spire, while its companion will have the spire longer than the body- 
whorl. One will be a giant, and another a pygmy ; and interme- 
diate forms occurring between these extreme varieties will so 
connect the whole that it would be impossible to separate them 
without doing violence to observed facts. 
I have five specimens of N. compta, A. Ad., all so named by 
men well known in the conchological world, and yet they are all 
different ; this being so, fixity of species seems to be relegated to 
transcendental conchology. 
The N. teenia, Gmel., passes into the N. canaliculata, Lam., the 
N. lens, Chem., the N. nitidula, Linn., and the N. trifasciata, Gmel. ; 
and the partially ribbed shells are intermediate between it and 
N. nodifera, Powis, into which it merges, and the small cancellated 
