Our pedi and many books agree that crawling is not a developmental milestone. Many skip it and it's ok to go straight to walking. Andy lunges forward but doesn't go anywhere else. He just rolls to his back. I wouldn't worry. Maybe start practicing walking? That's what we're gonna do.
Jenna still doesn't crawl but she is walking around (5 steps or so on average) and cruising a ton. I think she will skip it or I guess she will learn it at one point. I can't imagine she will be a teenager and not know how to crawl.
like the pp said...crawling is skipped at times as a milestone so i wouldn't be too concerned. my little guy crawled early. scooting around like an inch worm around 6 months and now has been crawling hands and knees for about a month or so.
Re: when did your LO start crawling?
from what I've read crawling is a developmental milestone.
https://www.babycenter.com/0_developmental-milestones-crawling_6501.bc
#2 & #3 Due 8/25/12