SUMMARY.Spinal afferent pathways ctwrcsponding to the classical somaesthelle projections, medial iemniscus and anterolateral column system, have been described for the marsupial phalanger, Trichosurus vulpecttla, using potentials evoked by limb stimulation.Potentials were also evoked within tlie central tegmental fasciculus and central grey which are considered to be phylogenetitally older somaesthctic systems. These projections ure relatively conspicuous in comparison with the classical paths, particularly the medial lemniscus. It is considered that the marsupial somaestheUc systems, with a dominance of medical indirect somacsthetic sensory p;iths, represent a step between the reptilian condition, where such patlis predominate, ynd the full development of more direct spinothalamJc projections in the higher mammals.