QUOTE(Car Expert @ Oct 9 2009, 12:32 PM)

QUOTE(dorfmouse @ Oct 9 2009, 09:02 AM)

Maybe more people can help if we know which Kp number is it ... there are rather a lot of Scarlatti sonatas!
There are indeed, but I believe the OP is referring to the piece in the current grade 6 syllabus.
Car ExpertIndeed he is, but not everyone can be bothered to look up the syllabus. Terrible, innit!!
My edition, EMB, Urtext, has the ornament notated as a demi-semiquaver appogg. In the foreward to the volumes the editor discusses at some length the inconsistencies of ornament notation in Scarlatti, and suggests that "... the frequently ambiguous notation gives the performer relatively wide scope to use his taste and imagination in finding the best solution ..." Further, "The general rule is that every ornament subtracts its value from the note which follows it. An exception is the anticipated appoggiatura which is always written out in rhythmic values." So, as I understand it, this is probably the case in bars 37 and 38.
I have a recording of Pletnev playing this sonata deliciously ... he plays them as little grace notes.