Showing papers in "Transactions of The Royal Society of South Africa in 1971"
TL;DR: An account of the present state of knowledge of the sandy-beach snail, Bullia, on the beaches of the Cape Peninsula is given, which deals mainly with the two surf-loving species, B. digitalis and B. rhodostoma.
Abstract: Summary This paper gives an account of the present state of our knowledge of the sandy-beach snail, Bullia, on the beaches of the Cape Peninsula. The work deals mainly with the two surf-loving species, B. digitalis and B. rhodostoma, though mention is made of B. laevissima, a species found in quiet waters. Reproductive behaviour is described for the first time. Much of the work reported concerns chemo-reception and the responses which lead to feeding. Some conclusions are reached with regard to growth and life-span. The distribution of the three species is dealt with, and the factors responsible for this distribution are discussed. Attempts to estimate the numbers of Bullia on Muizenberg beach are described. Some mention is made of water- and heat-relationships, defence mechanisms and parasites.
75 citations
TL;DR: In this paper, it is suggested that the gregarious roosting of A. ibis has been evolved primarily in relation to the food situation, and that communal roasting can be viewed as an extension of this behavior.
Abstract: Summary Roosting birds generally have two main requirements: protection from predators and shelter from adverse weather. The paper summarizes the results of some preliminary investigation into the significance of these conventions as they apply to Ardeola ibis. Communal roosting in birds has been little studied, and the function of this phenomenon is not yet understood. In A. ibis the whole advantage of social roosting cannot be explained only in terms of protection from predators, shelter for adverse weather and/or conservation of energy at night. Data are presented in support of the claim that in A. ibis an important, if not the main, function of communal roosting is in assisting individuals to maintain contact with each other. The value of this behaviour rests in more efficient finding and exploitation of localized food resources. It is suggested that the gregarious roosting of A. ibis has been evolved primarily in relation to the food situation, and that communal roosting can be viewed as an extension...
60 citations
TL;DR: Conditions on these beaches are described, with special reference to the beaches of Hout Bay, Llandudno, Milnerton and Muizenberg, where the more important members of the resident fauna of the beaches accorded special attention.
Abstract: Summary This is the first in a series of papers devoted to the ecology of the sandy beaches of the Cape Peninsula. Conditions on these beaches are described, with special reference to the beaches of Hout Bay, Llandudno, Milnerton and Muizenberg. Tidal conditions, wave-action, beach profiles and sand movements are discussed, while attention is also given to the particle-size distribution of the substrata forming the beaches. The organic content of the sand, its permeability and porosity, and the disposition of the water-tables are all discussed briefly and some data concerning salinities, temperature and pH are presented. Mention is made of the fauna and a list of the more important members of the resident fauna of the beaches accorded special attention is given. There is some attempt to show how the physical factors are interrelated.
39 citations
TL;DR: In this article, four marine Cretaceous samples collected from the Agulhas Bank are discussed and their ostracodal assemblages described, two of the samples are considered to be Lower-Cretaceous and the others Lower-Middle Senonian and Maastrichtian in age.
Abstract: Summary Four marine Cretaceous samples collected from the Agulhas Bank are discussed and their ostracodal assemblages described. Two of the samples are considered to be Lower Cretaceous, and the others Lower-Middle Senonian and Maastrichtian in age. Two new genera, twelve new species, and one new subspecies are described. Details of the foraminiferal assemblages are also given.
25 citations
TL;DR: In this article, a comparative study of production in different regions of South Africa is presented, focusing on the upwelling area and the temperate selforganisation area.
Abstract: (1971). A COMPARISON OF PRODUCTION IN TEMPERATE SEAS AND THE UPWELLING AREAS. Transactions of the Royal Society of South Africa: Vol. 40, No. 1, pp. 17-33.
14 citations
TL;DR: The laboratory rearing of Parechinus angulosus (Leske) larvae revealed that larval metamorphosis occurred 56 days after fertilization and could be delayed at least eleven days in the absence of a suitable substrate.
Abstract: Summary A description of the laboratory rearing of Parechinus angulosus (Leske) larvae is given. The larvae are described from samples taken at intervals during the larval life history. At 15°C in the presence of autotrophic flagellates and diatoms as food, larval metamorphosis occurred 56 days after fertilization. Metamorphosis could be delayed at least eleven days in the absence of a suitable substrate.
13 citations
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13 citations
TL;DR: It is shown that at 15°C in the presence of autotrophic flagellates and diatoms as food, larval metamorphosis occurred 41 days after fertilization.
Abstract: Summary A description of the laboratory rearing of Echinolampas (Palaeolampas) crassa (Bell) is given. The larvae are described from samples taken at intervals during the larval life history. At 15°C in the presence of autotrophic flagellates and diatoms as food, larval metamorphosis occurred 41 days after fertilization.
11 citations
TL;DR: In this article, the location, physiography and climate of the dune forest in the vicinity of Lake Sibayi is given, and the general ecology of the forest, with particular reference to composition and density of trees and shrubs, is outlined.
Abstract: Summary The location, physiography and climate of the dune forest in the vicinity of Lake Sibayi is given. The general ecology of the forest, with particular reference to composition and density of trees and shrubs, is outlined. The results are discussed in relation to survival of the most important canopy trees. It is concluded that the forest represents a stable vegetation type, i.e. Climax Dune Forest. A preliminary list of plants collected in the dune forest is appended.
10 citations
6 citations
TL;DR: A systematic report on the Anthicidae (Coleoptera) collected at three different localities in northern Zululand, with notes on the distribution of the mentioned species and description of eleven new species.
Abstract: Summary A systematic report on the Anthicidae (Coleoptera) collected at three different localities in northern Zululand, with notes on the distribution of the mentioned species and description of eleven new species.
TL;DR: A simple, automatic servomechanism for controlling closely the O2 tension in aquaria is described.
Abstract: Summary A simple, automatic servomechanism for controlling closely the O2 tension in aquaria is described.
TL;DR: Evidence is presented that rerouting via the hexose monophosphate shunt during temperature acclimation does not occur and the temperature history of the fish has insignificant effects upon the Vmax of brain or liver dehydrogenases.
Abstract: Summary The in vitro activities of the two dehydrogenases of the hexose monophosphate shunt have been measured in muscle, brain and liver extracts of Tilapia sparrmanii. Muscle extracts have negligible or no activity, and the temperature history of the fish has insignificant effects upon the Vmax of brain or liver dehydrogenases. Evidence is presented that rerouting via the hexose monophosphate shunt during temperature acclimation does not occur.