Experiments involving the recording of impulses in sensory nerves in the appendages of a scorpion and an amblypygid show that the slit sensilla (lyriform organs) of these arachnids are mechanoreceptors, sensitive to strains in the cuticle and analogous to the campaniform sensilla of insects.

The experimental work reported here was carried out during 1953 in the Department of Physiology, University of Ceylon, Colombo, and in the laboratory of the Division of Entomology, Department of Agriculture, Peradiniya, Ceylon.