ELEVEN FIQURESI n the first paper of this series (Ingle, '33) the rate of reproduction and the duration of life of parthenogenetically produced females of Daphnia longispina and hloina macrocopa were studied in relation to effects produced by semistarvation. It was found that this treatment produced a marked decrease in reproductive rate and a significant increase in length of life as compared with normal well-fed individuals. Well-fed Daphnia averaged 21.5 young per brood and 29.9 days of life, while their semi-starved sisters on the average produced only 5.5 young per brood but lived 41.4 days. It was concluded that semi-starvation influenced the rate of development and reproduction in several different ways and increased longevity.The early experiments indicated that limitation of food influenced Daphnia longispina in the following readily measurable characteristics ; longevity, reproductive rate, maximum body size (length), amount of and period of their greatest growth, duration of instars and rate of heart beat.Additional experiments were designed to test the effects not only of semi-starvation throughout life as revealed in these A portion of this paper was submitted in partial fulfillment of the requirements Doctor Iugle is now l o c n t d a t the Whitman Zoological Lahoratory, The for the degree of Doctor of Philosophy a t

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