[R] Plot symbols for more than 25 groups

[Marc R. Feldesman]

At 05:16 AM 4/2/2004, Carlisle Thacker watched in amazement as electrons 
turned into magical things called words:
 >Marc,
 >
 >It is very difficult for the eye to distinguish even 25 symbols or 25
 >colors on the same plot.  I find that my brain tends to saturate at 5 of
 >each, and using 5 symbols each taking five colors to get 25 groups is
 >hard to comprehend unless there colors and symbols correspond to quite
 >different characteristics of the data.   Maybe there is a better way to
 >display your data.
 >

This is a straight plot of the bivariate means of 38 different groups of 
primates.  We've already stripped out the data scatter around each mean, 
but we want to highlight where each group lies in the 2-dimensional 
space.  We haven't found a more effective way to illustrate this in a 
single plot than using a simple bivariate scatter.