Don't let anyone, not even spellcheck, tell you that pituitous is not a word. Now why, exactly, we're talking about allergies and their associated bodily fluids to describe the average shipping art, well, I'll never know (and I'm happier for it).
I checked Wiktionary, but all it says is:
Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
Perhaps one of these "more recent senses" is applicable here? Though having said that, they've got ship, and I bet that meaning wasn't in the 1913 Webster's.