These groups are:
The word "glyph" is derived from the the Greek word "gluphe" which means a carved or grooved channel. Thus the word "Aglyph" means "without a grooved channel". These snakes have no fangs with the characteristic groove necessary to transport venom. In general the more evolved a snake is the more the grooved channel is closed along its length to form a tube rather than a groove. The Aglyphous snakes include all non-colubroid snakes and many colubrids. In some cases the colubrids have actually lost their venom apparatus and fangs.
Skull of a Python
The python is well equipped with numerous large recurved teeth designed to assist it to grip its prey during constriction. The quadrate bone is short and massive and the mandible is relatively small. This type of skull is typically Aglyphous. There are no fangs and no poison apparatus.
Skull of a Mole Snake
Perhaps a better example of an Aglyph's skull is that of the Mole Snake. No venom apparatus and no fangs are to be seen. However these small teeth can be quite viciously employed and mole snake bites can be extremely painful. Loss of fingers has been recorded as a consequence of a mole snake bite.
A Green Tree python demonstrating its aglyphous teeth. It has no fangs.
Opisto - derived from the Greek "Ophisto" meaning "behind". The opisto- or ophistoglyphs represent that group of snakes known as the "rear-fanged" group. This type of dentition is often encountered in colubrids. Our best examples are the Boomslang and the Vine snake - the bite of both can be fatal to humans.
Skull of a Boomslang
An Opistoglyphous sandsnake shows it small rear fangs.
Skull of a Cobra
A Green Mamba shows its proteroglyphous front fangs.
Skull of a Puff Adder
Fangs of a Puff Adder
The hollow or grooved nature of the fangs of the puff adder are clearly visible in this photograph.
Venom gland and fang of a Puff Adder
The well-developed venom apparatus and fang of a puff adder can be seen in the above photograph. The venom gland is in actual fact a modified salivary gland and is linked to the groove in the fangs by a duct.
A Desert Horned Viper gives evidence of its Solenoglypghous fangs.