MeSH definition : A subfamily of snakes commonly known as pit vipers, crotaline snakes, or pit adders
in the family VIPERIDAE. They are distinguished by a deep pit called a fossa or loreal,
which functions as a heat-sensing organ located between the eye and nostril on either
side of the head.;
A subfamily of snakes commonly known as pit vipers, crotaline snakes, or pit adders
in the family VIPERIDAE. They are distinguished by a deep pit called a fossa or loreal,
which functions as a heat-sensing organ located between the eye and nostril on either
side of the head.