[log in to unmask]  wrote:

Now that you have decided on what species is---or may be, I wonder if
there is a decent description of the
difference between "sub-species" and "form of-".

I get the digest form of Conh-l so i may be repeating someone else's
reply here.  But, what the heck!!  A "form" or "variety" (and the two
are used almost interchangeably in the literature, so that efforts to
distinguish between them would not be very useful) is either a) a
locally common, (or locally endemic) variant that is distinct enough to
warrent a name - such as Cymbiola aulica forma palawanica Doute, which
is a striking local form well worthy of such status, of b)  a distint
variation which occurs along with other variations in populations over a
good -sized portion of a species' range - such as Chlamys opercularis
forma lineata da Costa, which is a very distinct pattern variant in that
species.  It is an regrettable fact that many forms/varieties are
superfluous to any real understanding of a species - variable cowries
and cones in particular tend to gather hordes of varietal designations,
many of dubious utility to anyone except collectors who wish to add
named forms to their collection (a valid avocation, i might add, at
least from a dealer's viewpoint ;--}).//  "Subspecies" on the  other
hand, are clearly separate populations or groups of populations of a
species that are 1) easily distinguishable from the nominative form of
the species, and 2)  geographically or possibly in some cases
ecologically isolated, so that they do not normally interbreed with the
nominative form.  A good example of this is Neptunea lyrata decemcostata
(Say), which is the Atlantic subspecies of N. lyrata (Martyn).

Stricly speaking then, there is quite a difference between a form or
variety and a subspecies: both are distinct, readily discernable (at
least in theory!!) variants of a species, but the latter is genetically
isolated from the nominative form, usually on a regional but in the case
of poorly dispersing species such as many volutes, sometimes locally.

From the reasonably chilly North (-22 C yesterday),
Ross mayhew.