William Thomas Calman, 1911 Encyclopædia Britannica, Volume 7… (1911)
“ Other species of the genus are found in central and eastern Europe and as far east as Turkestan. Farther east a gap occurs in the distribution and no crayfishes are met with till the basin of the Amur is reached, where a group of species occurs, extending into northern Japan. In North America, west of the Rocky Mountains, the genus Astacus again appears, but east of the watershed it is replaced by the genus Cambarus, which is represented by very numerous species, ranging from the Great Lakes to Mexico. Several blind species inhabit the subterranean waters of caves. ”
