Reptiles are a class of cold-blooded (in the traditional sense) animals that include the turtles, crocodiles, snakes and lizards. They first appeared on earth during the Carboniferous around 312 million years ago and a staggering 10,000 species have since been described. The majority (95%) of these species sit within the Squamata group that holds the lizards, snakes and “worm lizards”.
Britain’s Reptiles & Amphibians - by Howard Inns
WildGuides Ltd. -- 2011 -- ISBN: 978-1903657256
Collins Field Guide: Reptiles & Amphibians of Britain & Europe - by Nicholas Arnold & Denys Ovenden
HarperCollins -- 2004 -- ISBN: 978-0002199643