The pronephric systems of eight Neoceratodus larvae ranging from 11·5 to 16 mm. total length were analysed quantitatively and the measurements were treated statistically for two groups of mean total length 11·5 mm. and 15·3 mm. In the 15·3 mm. group the means of the measurements of the nuclear population, total volume of cells, overall pronephros volume and the internal surface area of the tubules show a significant superiority over the means of those in the 11·5 mm. group, but the mean of the glomus length is significantly lower. The individual cell volume which does not change significantly had a maximum range of 6500–6800 μ3. Quantitatively in terms of cell volume and qualitatively the pronephric systems of larvae of Neoceratodus, Anura and urodeles are similar, and have evolved in a parallel manner during phylogeny.