Boulenger rightly considers this snake in various ways intermediate between the Ilysiidae, Boidae and Colubridae.
All Boidae possess vestiges of pelvis and hind limbs, appearing externally as claw-like spurs on each side of the vent, but they are so small that they are practically without function in climbing.
Ilysiidae Xenopeltidae Colubridae Aglypha Typhlopidae Boidae Glauconiidae 'This means that the Boidae retain most primitive characters.
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.
The Boidae comprise some 60 species, which have been grouped into many fancy genera.
The solitary Xenopeltis is in several ways intermediate between Boidae and Ilysiidae.