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]
^Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. ISBN0-88359-029-8.
^Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company, Malabar, Florida. ISBN0-89464-877-2.
^Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN0-8014-4141-2.
^Wareham, David C. 2005. Dictionary of herpetological and related terminology. Elsevier. ISBN0-444-51863-0