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M. J. Boddington, D. F. Mettrick, The Distribution, Abundance, Feeding Habits, and Population Biology of the Immigrant Triclad Dugesia polychroa (Platyhelminthes: turbellaria) in Toronto Harbour, Canada, Journal of Animal Ecology, Vol. 43, No. 3 (Oct., 1974), pp. 681-699
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Boddington et al. (1974) studied this question.
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