The suture between the two halves of the Frontal
bones is
Frontal bone ossifies in membrane. 
It develops from 2 centres near frontal eminences, during 8th week of intrauterine life.
At birth, the bone is in 2 halves, separated in the midline by a suture, known as metopic suture, which soon starts to fuse.
The metopic suture occasionally persists in 3 to 8% of individuals.
Metopic
Symphysis
Mendosal
Coronal