SOME FRESH-WATER CALANOIDS DIRECT OBSERVATION v. INDIRECT DEDUCTION.

The article discusses various observations made by Charles S. Elton, author of the book "Animal Ecology," regarding the population of fresh-water Calanoids, Diaptomus gracilis and Eurytemora, in the filter-tanks of the Oxford Corporation Waterworks. It offers information on a series of breeding experiments carried out in the waterworks during the period of September to November 1929 to present various facts with regard to the Elton's statements such as that Diaptomus gracilis does not live in the filter-tanks because its eggs cannot withstand being dried up and the Eurytemora population was derived from resting eggs that had survived the drying process. It is inferred that contrary to the Elton's statement, the resting eggs of Eurytemora play no part in the population of the filter beds.