For those who might like to count the very fine teeth of very
small cowries, try the sharp-pointed X-Acto(R) No.11
(STAINLESS STEEL, very important) blade as a counting tool.
 
That is, carefully (VERY carefully) draw the tip of the sharpened
edge lightly over the teeth, counting the quite audible 'clicks' as it
goes from one tooth to the next. (Having the blade in a handle
really helps.)
 
It worked for me on hundreds of Cypraea fimbriata and semiplota;
even on my 9.5mm C. isabella with more than 20 labial teeth. The
trick is holding the shell steady. And do not use pressure. If you
slip, under pressure,... Ouch!!
 
Good luck.
 
Aloha,
 
makuabob (a.k.a. Bob Dayle)