Canthus (herpetology) explained

In snakes and amphibians, the canthus, canthal ridge or canthus rostralis,^[1] is the angle between the flat crown of the head and the side of the head between the eye and the snout,^[2] or more specifically, between the supraocular scale and the rostral scale. It is defined as a sharp ridge in many viperids, but is rounded in most rattlesnakes, for example.^{[3] [4]}

Notes and References

1. Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. .
2. Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company, Malabar, Florida. .
3. Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. .
4. Wareham, David C. 2005. Dictionary of herpetological and related terminology. Elsevier.