In scans of early printed books which use an italic type, I've sometimes seen an alternate letter form used at the end of a line where some extra space needs to be filled up. This alternate form ends with a long baseline swash to fill up the extra space. I can't find an example of this from an actual book, but these alternate characters look like this "m" from a sample of Cancelleresca Bastarda:
Is there a more specific name for this type of swash, which is more for filling up space than for ornamentation, which can extend a long distance when necessary, and which sticks to the baseline more than a decorative swash would?