Natrix
Natrix is a genus of Old World snakes found across Eurasia (Although "Natrix tessellata" can be found in Egypt and "Natrix natrix" can be found in other parts of Northern Africa) in the subfamily Natricinae of the family Colubridae. Common names. Member species of the genus "Natrix" are collectively called grass snakes and water snakes, but some other snake species also known commonly as "grass snakes" and "water snakes" are not in the genus. Species. The genus "Natrix" contains these species, five of which are recognized as being valid, and one of which is disputed: "Nota bene": A binomial  authority in parentheses indicates that the species was originally described in a genus other than "Natrix". Etymology. "Natrix" is classical Latin for a water snake. The word comes from a Proto-Indo-European root meaning "snake", with cognates in the Celtic and Germanic languages, the latter including the English adder. It was probably influenced through folk etymology by the Latin "nare" and "natare" meaning "swim"; it appears to be a grammatically feminine word for "swimmer". Geography. The refuge of a widely distributed Western European lineage regarding the barred grass snake commonly known as "Natrix helvetica "was most likely located in  southern France and outside the classical refuges in the southern European peninsulas. One genetic lineage of the common grass snake ("N. natrix") is also distributed in Scandinavia, Central Europe, and the Balkan Peninsula.