- Without supraorbital bones.
Attached to it or the neighbouring frontal is often a supraorbital; infraorbitals occur also, attached to the jugal or downward process of the lacrymal.
Large supraorbital glands.
- With a pair of supraorbital bones between the prefrontal, frontal and postfrontal bones.
BOA, a name formerly applied to all large serpents which, devoid of poison fangs, kill their prey by constriction; but now confined to that subfamily of the Boidae which are devoid of teeth in the praemaxilla and are without supraorbital bones.