I assume that when it says '-US -I -UM' for QUARTUS that it
means that it declines like a masc adj in the 1&2 declension:
Also, off the subject of numbers, the cardinal numbers are followed
by EX using the ablative. Such an example is 'one from the book'
or 'UNUS EX LIBRIS'. I suppose this would not change the grammar
if the sentence was 'That one from the list was used' or even more
complex forms with the negative such as 'Not that one from the list,
but the other one'