The class Reptilia consists of 6 orders, 67 families, about 1,900 genera and some 9,766 species. They are distributed on every continent with the exception of Antarctica. About 340 species can be found in North America north of Mexico. Reptiles range in size from the 16 milimeter (0.63 in) Jaragua Sphaero Sphaerodactylus ariasae to the 8 meter (26 ft) Green Anaconda Eunectes murinus.