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The salinity tolerance of some Eastern Province fish in relation to their known distribution

- Hofmeyr, Hendrik Petrus

Authors: Hofmeyr, Hendrik Petrus
Date: 1966
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:21165 , http://hdl.handle.net/10962/6684
Description: The tolerances to sea water, sodium chloride and sodium sulphate of various cichlid, cyprinid and anabantid species which occur naturally in or near the Eastern Province region of Southern Africa, were determined, and correlated with their distribution ranges. Of the nine freshwater species tested, only Tilapia mossambica is able to disperse through the sea and is therefore the only member of the secondary division (Myers 1937) present in this region. The remaining species are possibly all limited to the use of freshwater links for dispersal between river systems. Death of fish in sea water and in sodium chloride is chiefly due to loss of osmotic control, but in solutions of sodium sulphate a pronounced toxic effect is responsible for death. In all the solutions used, an inverse relation between survival time and concentration is present. No evidence of any cells specialised for salt excretion was found in the gills of fish exposed to various salt concentrations.
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Date Issued: 1966

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On the physiology of the lantern retractor muscle of Parechinus angulosus

- Boltt, R E

Authors: Boltt, R E
Date: 1963
Subjects: Echinodermata -- Physiology
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5900 , http://hdl.handle.net/10962/d1013513
Description: From Resumé: The lantern retractor muscles of regular echinoids act in almost isometric conditions and a study of their control was considered to be of interest. The retractor muscles cannot be indirectly stimulated from the radial nerves, but proved to be very photosensitive. Their responses to light were therefore studied. The muscles show a complex pattern of contraction in response to illumination, which includes both excitatory and inhibitory components. The possible genesis of these patterns is discussed and examined in the light of the responses of the muscles to direct current stimulation and to drugs. It is concluded that many of the features of the response are undoubtedly neurogenic in origin, but that myogenic activity may possibly also be involved.
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Date Issued: 1963

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Studies on the neuro-physiology of a free-living Platyhelminth

- Boyle, Sheila A

Authors: Boyle, Sheila A
Date: 1961
Subjects: Platyhelminthes
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5902 , http://hdl.handle.net/10962/d1013541
Description: From Resumé: The general picture of the physiology of invertebrate neuro-muscular systems as contrasted with the classical vertebrate system is presented and it is clear that one of the groups least investigated is the Phylum Platyhelminthes. An examination of the properties of the myo-neural system of a platyhelminth should be of interest, not only in itself, but also because of a possible relationship with the coelenterates, whose neuro-muscular system has been fairly extensively investigated. The aim of the present work was to determine some of the properties of the myo-neural system of a platyhelminth, and more especially those which would make possible a comparison with the myo-neural systems of other invertebrate phyla, and most particularly with the coelenterates. A preparation consisting of an entire decerebrate animal was used. The general anatomy of the musculature and basic plan of the nervous system are presented to facilitate an understanding of the experiments described, but a detailed examination of the relationships of nerves and muscles or of the innervation of the latter was not attempted. The spontaneous activity of such preparations was recorded kymographically and the characteristics of this activity under 'normal' conditions are described, together with observations on the effects on the normal spontaneous activity of treatments with sea waters of different ionic composition and with a number of drugs. The responses of the preparation to controlled electrical stimulation are also reported. The results are analysed and compared with the results of similar investigations on other invertebrate preparations, in particular the Anthozoa, and an interpretation of these results in terms of platyhelminth-coelenterate relations is discussed.
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Date Issued: 1961

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Contributions to the biology, anatomy and physiology of Opisthophthalmus Latimanus & other scorpions

- Alexander, Anne Joy

Authors: Alexander, Anne Joy
Date: 1958
Subjects: Scorpions -- South Africa , Scorpions -- Anatomy , Scorpions -- Physiology
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:5891 , http://hdl.handle.net/10962/d1013375
Description: [From Introduction] For many years the problem of interrelationships within the Arthropoda and, indeed, the origin of the Phylum itself have been of interest to many zoologists. It was felt, for reasons which will be given later, that one of the studies which might throw some light on this matter is that of the neuromuscular physiology of arachnid appendages. Consequently it was proposed that the work which is reported here should be primarily concerned with this problem. As in so many cases involving live animals, both the experimental subjects and the experimenter gradually managed to change the direction in which work was proceeding and the result is that only a preliminary attack has been made on the original problem, while most of the material submitted here deals either with functional anatomy or with biological-cum-behavioural characteristics of the experimental animal. Thus it was found that to develop experimental preparations for neuro-muscular studies, it was necessary to work out the anatomy of the muscles and nerves of the appendages used; but this it is not enough. For these nerves and muscles are part of a functional complex which operates as a unit and have therefore to be studied in relation to the structures that they move. Considerations at this level, in fact, carried the study to the plane of functional anatomy. Furthermore it was recognised that even the comprehension of a limb as a functional complex cannot be acquired in isolation. All structures have an evolutionary history and in any consideration of functional anatomy this history must be taken into account - even if the consideration requires extension to the problem of the origin of the group immediately under study.
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Date Issued: 1958

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Correlation of the feeding habits, jaw musculature and type of teeth of some South African golden moles

- Thelejane, Thomas Sohl

Authors: Thelejane, Thomas Sohl
Date: 1958
Subjects: Moles (Animals) -- Food , Insectivores (Mammals)
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5892 , http://hdl.handle.net/10962/d1013385
Description: The jaw musculature and its innervation in the Chrysochloridae studied is typicaly mammalian except that the m. temporalis occupies the whole of the orbito-temporal fossa. The antemolar teeth are specialized, while the molars are simple and primitive. Normally the diet of Golden Moles consists of earthworms, insects in all stages of development and millipedes. The firm implantation of the antemolar teeth can be correlated with their function of catching the prey, while the molars are adapted for a worm-like diet. The available evidence indicates that the genera Bematiscus and Chrysospalax are more primitive than the other Golden Moles. Since Golden Moles feed on insects in all stares of development and millipedes, they can be considered as being of economic importance.
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Date Issued: 1958

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Some aspects of the animal ecology of Rhenosterbos: Elytropappus rhinocerotis (L.f.) Less

- Shiff, Clive Julian

Authors: Shiff, Clive Julian
Date: 1957
Subjects: Animal ecology -- South Africa , Rhenosterbos
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5880 , http://hdl.handle.net/10962/d1013200
Description: Rhenosterbos, Elytropappus rhinocerotis (L.f.) Less belongs to a purely South African section ot the Compositae. It is restricted to an area of low rainfall which is evenly distributed over the year. The plant is a specialised xerophyte with minute leaves and white pubescent twiglets. Older stems become woody and dry and bear no leaves. The shrubs have a life span of about eight years; the plants are most succulent and luxurious during the third and fourth year, after which they tend to become woody and scraggly. For this investigation insect material was obtained by sweep-net collection and field observation. In the Grahamatown district 78 collections were made during the period March - November 1953, with data thus obtained being embodied in this work. In addition to this, collections were made in the Cradock-Hofmeyer, Uitenhage, Riversdale, Bot River, Swellendam and Stellenbosch districts. Twenty species of insects have been shown definitely to feed on the plant and there are another 13 which probably feed on it. Of the 20 species attached to the plant, 12 are sucking forms belonging to the Orders Homoptera and Hemipters. They include six Coccids, two Jassids a Cercopid, two Mirids and a Pentstomid. The Coleoptera are represented by one or perhaps two species which feed on the plant. The Lepidoptera are represented by two important species of moth, a Geometrid and a Pyralid. Four species of gall forming Diptera are associated with the plant. There are two species of Trypetidae which are responsible for piriform swellings of growth points and are distributed evenly throughout the bush. There are also two Cecidomyidae one of which develops in the growth points of the shoots and is responsible tor a minute tubular gall. The other develops in a fusiform stem gall. This latter gall has been shown to be more common on smaller bushes than on larger ones, implying that the adult female may show certain selective powers during oviposition. The size of the insect population is held in check by spiders mantids and other general predators. There are several Coccinellids which prey on the scale insects. Rhenosterbos supports a small, well regulated community of insects. The balance between plant and animal is very dellcate because of the high degree of specialisation of the plant. On occasions this balance has been known to break down, and the insects present in abundance have swamped and killed large patches of the plant.
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Date Issued: 1957

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A preliminary investigation of the ecology of the Larger Kleinmond River Estuary, Bathurst District

- Brown, Alexander Claude, 1931-2005

Authors: Brown, Alexander Claude, 1931-2005
Date: 1953
Subjects: Kleinemonde River Estuary (South Africa) , Estuaries -- South Africa , Estuarine ecology -- South Africa
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5904 , http://hdl.handle.net/10962/d1014611
Description: Introduction. On the coast of the Bathurst Division, Eastern Cape Province, some 42 miles south- east of Grahamstown, lie two estuaries opening within a few yards of one another. These are known as the Kleinemonde. This paper embodies the results of an ecological survey of the fauna of the Larger Kleinmond Estuary. The chief concern has been the aquatic fauna but animals living along the banks have also been dealt with as far as possible, as have the birds. This is the second of South Africa's blind estuaries to be studied, the Klein River, Hermanus, having been investigated in 1947-49 by workers from the University of Cape Town. Though common in South Africa, blind estuaries are rare in parts of the world such as Europe, and present an almost entirely new field of research for the ecologist. It is hoped, therefore, that the investigation of the Kleinmond Estuary and a comparison with the results obtained from the Klein River, Hermanus, will add to our knowledge of this subject and be of service to future investigators. The history of the Kleimnond River is worthy of mention, for the lagoon was not always blind and shallow. The early maps of the 1820 settlers show the river as a navigable stream; sailing vessels anchored out at sea and sent lighters up what was then known as the Lydendoch River to collect fresh meat. The area at the mouth of the river was called Port Jessie. In these early days the region abounded with game. Hippo and elephant were common. the former inhabiting deep pools in the upper reaches of the river; pools which have since completely silted up. Constant ploughing of the slopes adjoining the river has caused vast amounts of soil to be washed by rains into the stream, and today what was within living memory a deep, clear stream is a shallow, blind and muddy river, a reflection of man's destructive methods of farming. These changes must have had a far-reaching effect on the fauna of the estuary; an effect about which we can, alas, only speculate. It is perhaps significant that though rich in numbers, the fauna is poor in species, tunicates and echinoderms being apparently entirely absent. The work involved in this survey was undertaken between September 1952 and November 1953, under the direction of Professor J . Omer-Cooper of Rhodes University, frequent and regular visits being made to the estuary. The entire month of February, 1953, was spent on the shore of the lagoon, so that animals could be observed over a continuous period. The starting date of the survey was particularly fortunate, as on September 28th, 1952, the river came down in flood and broke through the sand-bar separating the lagoon from the sea. The work thus began at a definite point in the estuarine cycle, the importance of which it is hoped to show.
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Date Issued: 1953

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The morphology and biology of Anomala vetula Wied : an arthropod pest of turf in South Africa

- Bradford, B

Authors: Bradford, B
Date: 1946
Subjects: Anomala
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5903 , http://hdl.handle.net/10962/d1013545
Description: From Introduction: For the past eight years, the Zoology Department of Rhodes University College, in co-operation with African Explosives & Chemical Industries Ltd., has been studying certain entomological problems relating to turf on the golf course along the coastal belt of the Eastern Cape Province. The position is briefly as follows:- On the golf courses at Mossel Bay, Humewood (Port Elizabeth), Port Alfred and East London, vast damage has been done to the greens and fairways by "white grubs", the larval stages of Scarabaeidae. It would appear that these beetles had been present in the environs of the courses for many years, but it was only when large areas of the natural veld were converted into fairways, with a more or less uniform cover of grass, with Cynodon dactylon Pers. predominating, that conditions were inadvertently created which favoured the development of the beetles. It was not long after the establishment of these golf courses, that the beetles assumed the proportions of a pest, and the larvae began destroying the root system of the grasses covering the greens and fairways.
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Date Issued: 1946

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The Anatomy of Microchaetus Saxatilis: with some notes on allied species

- Louw, M A

Authors: Louw, M A
Date: 1941
Subjects: Uncatalogued
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10962/193666 , vital:45382
Description: Earthworms of the genus Microchaetus, Rapp.1849, are abundant in the Grahams town district. Microohaetus saxatilis, Rosa, 1S98,has been chosen as a subject for investigation as it is a valuable type for laboratory work, and it showed interesting characters which required detailed study. Members of the genus Micro chaet us are available in many regions of South Africa and are useful for work in South African schools and Universities. Micro chaetus saxatills is an 01igochaete worm belonging to the family Glossoseolecidae. These wonns were originally placed in the Lumbricina by Grube, (1850 p.345), but Rosa in 1887 (p.7) formed a separate family naming it the Geoscolecidae. He divided it into two sub-families :- (1) Geoscolecinae, and (B) Microchaetinae. Beddard was studying the classification of this family at the same time as Rosa. He spelt the name slightly differently, calling the family the Geoscolicidae, but he arrived independently at the same division into subfamilies (1888, pp. £43-278), although he suggests that perhaps an additional sub-family - the Homo gas. tridae - should be formed. Homo gas ter is undoubtedly an aberrant type, and it seems strange that Rosa who studied this genus should not have placed it in a separate sub-family. , Thesis (MSc) -- Faculty of Science, Zoology, 1941
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Date Issued: 1941

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