Actually my GM says SR applies to all SP's regardless of any other factors ... If it has a (sp) beside it SR applies even if the spell dates SR doesn't apply.
I am think if the underlying spell says the SR doesn't apply then SR doesn't apply even if it is an SP
(More how it is defined in the Universal Monster Spell like Ability description "They go away in an antimagic field and are subject to spell resistance if the spell the ability is based on would be subject to spell resistance.")
Is there a Acidic Ray Spell description anywhere?