A criticism of statements regarding the interrelationships of Eurytemora lacinulata and Diaptomus gracilis, and also on the seasonal distribution of certain species of Cyclops, made by C. Elton in his book on Animal Ecology. Elton stated that E. lacinulata is limited in its inland distribution to ponds not containing Diaptomus, and that these ponds are all artificial and fairly new. Evidence is given of the occurrence of E. lacinulata in older ponds and lakes, and in company with Diaptomus. The statement that D. gracilis has poor powers of dispersal and therefore does not reach new ponds quickly is controverted. A further statement by Elton that Cyclops strenuus is a winter sp., being replaced by C. juscus and C. albidus in summer, is challenged and evidence given that the latter 2 spp. are found together all the year round. [See Entry 7825 in this issue.].