Ortmann has traced the centre of dispersal of the fresh-water Crawfish genera Cambarus, Potamobius and Cambaroides to eastern Asia, where their common ancestors lived in Cretaceous time.
All the known forms of plant-life are either fungi or allied to them, and many are only microscopic. The most interesting inhabitants of Mammoth Cave are the blind, wingless grasshoppers, with extremely long antennae; blind, colourless crayfish (Cambarus pellucidus, Telk.); and the blind fish, Amblyopsis spelaeus, colourless and viviparous, from 1 in.
The Cambarus and Amblyopsis have wide distribution, being found in many other caves, and also in deep wells, in Kentucky and Indiana.
Blind crawfish (Cambarus pellucidus)inhabit the Crawfish Spring.