Hello Mr. Sim,

In Picture #1, shell #1 is a Lima (family Limidae).  You didn't say
which coast of Mexico it is from.  If it is from the Caribbean side, it
is probably Lima lima (L.).  If it is from the Pacific coast, it could
be Lima tetrica Gould.

Shell #2 is a "Calliostoma type" shell, not an actual Trochus, and
certainly not a Bolma.  It may be an Astele, possibly Astele bularra
Garrard, but probably something else in that general category.

Shell #3 appears to be Cuma lacera (Born). The detachment of the last
whorl from the previous whorls is not a normal characteristic of the
species, just a fluke of your specimen.

Picture #2 - shows some of those terrestrial-type thingies.  I'll pass.

Picture #3 - Shell #P1 appears to be Chlamys macassarensis (Chenu).  It
could be Chlamys reevei (Adams & Reeve), which some authors consider to
be a form of C. macassarensis.

Shells #P2 and P3 both show markings and rib counts typical of Chlamys
tranquebaricus (Gmelin), but in the picture they (especially P3) appear
too inflated to be that species.  It's hard to tell.  The pictures are
not clear enough.

Shell #P4 appears to be Pecten (Gloripallium) pallium (L.), but from the
picture provided, I can't completely rule out Gloripallium speciosum (Reeve)

Regards,
Paul M.