From Jeff Kula of Uhrichsville, Ohio:
A while back ItsAWrap had auctioned off Spock's spacesuit from Star Trek:TMP. In describing the helmet it was mentioned that it had a hole/slit carved on the top.
I was over on TVLand's website and caught an interview with a few of the cast members (Takei, Nichols, & Koenig). In Part 3 of the Live Chat Walter Koenig said what they did was they had to cut a hole on top of the helmet to be able to drag/manipulate the worm going across the face. Cool piece of info. Here's the link....
(Click on Pre-Recorded Live Chat located on the left)
Part 3 talks about the helmet / worm.