County Clare comprises (or comprised) all or parts of nine Poor Law Unions (PLUs, now known as Superintendent Registrar's Districts or SRDs):
These are the spellings which appear on the map athttp://www.logainm.ie/eolas/Data/Brainse/sw-sheet.jpg
However, athttp://www.workhouses.org.uk/Ireland/Un ... land.shtml
no less than five of the nine are spelled differently:
Searching the Irish Civil Registration Indexes, 1845-1958 for births, marriages and deaths in Clare obviously requires a knowledge of the possibility that insisting on exact matches might miss a spelling variant in the PLU/SRD name.
So I did some counts using the ancestry.com version of the database.
Ballyvaghan: no births, no marriages, no deaths
Ballyvaughan: 7,658 births, 2,884 marriages, 5,392 deaths
Corofin: no births, no marriages, no deaths
Corrofin: 9,364 births, 3,420 marriages, 6,181 deaths
Ennistimon: 37,806 births, 11,919 marriages, 22,885 deaths
Ennistymon: no births, no marriages, no deaths
Ennis: 47,445 births, 22,277 marriages, 36,927 deaths
Kildysart: no births, no marriages, no deaths
Killadysert: 18,598 births, 7,439 marriages, 11,657 deaths
Scariff: no births, no marriages, no deaths
Scarriff: 27,952 births, 12,824 marriages, 20,290 deaths
The bottom line is that the ancestry.com database is internally consistent as regards spelling of PLU/SRD names, but uses the spellings from the map for Corrofin, Ennistimon, Killadysert and Scarriff, but the alternate spelling for Ballyvaughan.