Temperature, turbulence, oxygen, and notonectid predators (Anisops calcaratus) were studied experimentally as possible factors influencing crest growth in six different forms of the Daphnia carinata complex. Predators were the most potent influence, inducing crest development in four of the morphs. Temperature had only a secondary effect which may have been indirect. When the notonectids were partitioned off from the Daphnia in the same container, crest development still resulted, suggesting that the stimulus was a water-soluble secretion from the predator. If the notonectids were starved this secretion was either not produced or was ineffective. Experiments showed that predators could induce crest development in adult daphnids that were initially uncrested and that a sustained stimulus from the predator was necessary if crested juvenile Daphnia were to produce crested adults. Under experimental conditions, daphnids with a crest were less susceptible to notonectid predation (mainly because of superior evasion powers) than were those without one. Results of a regression analysis of field data were broadly consistent with experimental results, especially in indicating that predation was a potent factor influencing crest development, and the distribution and abundance of morphs.

Chemical and biological data for a number of saline lakes in south-eastern South Australia and western Victoria are presented and discussed. The chemical information includes discussions on the major ionic composition of the lakes in March 1964, on the nature and extent of seasonal variations in the concentration of total dissolved solids in these lakes, and on the nature and extent of secular variations in salinity at Lake Corangamite. The biological data (almost exclusively faunal, and based mainly on a single series of collections made in March 1964) are discussed with particular reference to affinities, tolerance to high salinities, level of endemicity, uniqueness, and related topics. It is concluded that the fauna is different in many respects from that of similar habitats outside Australia.

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New populations of the two species of calanoid copepods known to inhabit freshwater lakes in East Antarctica, Boeckella poppei (Mrázek, 1901) and Gladioferens antarcticus Bayly, 1994, have recently been discovered. The morphology of the populations of B. poppei showed significant differences,