Since nobody has answered Moshe's enquiry, i will take a stab at it,
although i am certainly not as qualified as some:   Cyp. mus S.S. has a
rather limited range on the east side of the range of its larger form
Cyp. bicornis Sow. 1870 (donmoorei Petuch, 1979 is a synonym of
bicornis) - right up there on the edge of Venezuela.  Bicornis has a
very well developed margin (usually with a much broader and attractive
pattern than mus S.S.) which has a heavy calus anteriorly, which often
forms 1 to 3 prominant tubercules.  Many dealers (myself included, i
blushingly admit!) like to play around with the nomenclature a bit, and
call specimens with two well-formed tubercules "donmoorei bicornis", and
the rare examples of three tubercules "tricornis", just for the sake of
clarity, since most collectors are by now familiar with Petuch's name donmoorei.

Hope this clears things up!

From the great warming-up North (high today was 17!!);
-Ross.