Jim,
Are the lines visible on the negatives backlit under a loupe?
Was the film processed by a machine (not hand processed)?
If the answer is yes to both: The direction and uniformity of the lines suggests it is caused by the machine it was developed in.
There are racks on most processors with plastic rollers on them. Photo chemicals will, over time, leave deposits on the rollers which must be cleaned periodically. Cleaning racks and rollers involves dumping all the chemicals manually, cleaning with some strong solvent cleaners, and then remixing chems, getting them up to temp, testing.....it's a pain, so many labs don't do regular maintenance as they should, but rather wait for a problem to force them to fix it.
I've switched labs more times than I want to remember, but all it takes is one negligent owner, manager, employee, and you'll get scratches, spots, pressure marks, etc. Now if I can develop the film myself (B&W other than Ilford XP2), I will. Recently I've been sending my film (from Hawaii) to Utah to a lab I trust. There are two local labs in my area, but they are both inconsistent and there is nothing more aggravating than to pay money for someone else to mess up your precious film.
My favorite lab in California is A&I:
http://www.aandi.com/film/