It looks to me like the nozzle needs to be a little bit close to the bed. It looks like those open areas did not get the filament pushed down and stuck to the bed.

If you are running a recent version of Marlin, the Z-BabyStepping is really nice for this kind of problem. You can lower (or raise) the nozzle a little bit while it is printing and get the filament squished just the right amount.