Sixteen species of mites belonging to nine different families were found on Mus musculus and Apodemus hebridensis and in the nests of the former. Of these, eleven species may be regarded as parasitic in habit, two species have previously been recorded in association with rodents and moles, and three species may be described as accidental visitors.

I wish to thank Mr Elton and Prof. Munro of the Imperial College for their help, and I am also greatly indebted to Dr Caiman and Dr Finnegan for allowing me to make use of the facilities afforded by the British Museum (Natural History).