Dear Nancy, The information you require re:  proper names for Chlamys
vexillium & rubida is as follows:- Semipallium vexillium (Reeve,1853)  
Chlamys (Chlamys) rubida (Hinds,1845)    acc to A.Rombauts 'Guidebook to
Pecten Shells'.
I must pass on the common names, as I have found in the past, to my cost,  
that most shells have more than one common name and these names  can change
so quickly from area to area, (or worse still from judge to judge).  There
are at least 6 - 8 common names for Chlamys (Aquipecten) opercularis
(Linnaeus, 1758) within the British Isles and Northern France for example,
Queen Scallop, Queenie, Quin, Frill, just to name a few.  For this reason I
now tend to avoid common names in my exhibits, the latin name can cause
enough controversy
I am sorry that I cannot be more helpful.
Stanley Francis.(Northern Ireland)