Thanks to those who answered my Olividae plea.  Now, can anyone help me
obtain a copy of Cate, 1973, which is not at any local library?
 
PECTINIDAE is one of my very favorite families!!  When i think of the
concept "pecten", as per a recent post, images of riotous colors and
patters come to mind, and beautiful arrays of variation within most
species and local populations.  Take for example the relatively common
species Flexochlamys flexuosus Poli, which comes in all colors except 
blue and "true" green,  and has nearly 2 dozen quite distinct types of
patterns (ie, ways of forming their patterns), and  most specimens
display several contrasting colors.  The result is that they are like
snowflakes- to find two specimens even                 *approaching* 
being  nearly identical, is next to impossible!  Even cold-water spp,
such as Placopecten magellanicus Gmeilin and the North Sea spp, show a
delightful  range of color and pattern variability not common in
"cold-water shells", and add some "zing" to cold-climate collecting. 
Some people see the word "pecten", and immediately think "bivalve: i
don't collect these."  These poor folks do not know what the¥ are
missing.
                                                                                                -Ross M.