President' 's Address. V 



conjoined with a corresponding variation in salinity as indicating 

 that the cold waters of the west coast of the Cape are not merely 

 the welling up of the colder waters when the warmer upper layers 

 are driven away from the shore by winds ; no doubt much of the 

 variation in temperature can be brought about by such an agency, 

 but this very marked difference of temperature and salinity can most 

 satisfactorily be explained by the close proximity of the southern 

 drift current. 



The chart which I now show indicating the course of drift bottles 

 and the following section of the sea off the west coast of the Cape 

 Peninsula proves further that a small branch of the Agulhas current, 

 occasionally at least, escapes round Cape Point towards the west 

 coast. 



Having outlined the main physical features of South African 

 Waters as they are modified by the great ocean currents which meet 

 in this region, let us consider briefly some of the more local pecu- 

 liarities which are also important features in the moulding of the 

 character of the South African marine fauna. The feature of the South 

 African coast is its want of bays, natural harbours, or inlets, and of 

 any islands or large fresh-water inlets, all of which in some other 

 countries give rise to peculiar modifications of sea-life. Although, 

 however, there is not a single large river which does not admit the sea 

 for several miles inland, all are capable of swelling into floods of 

 great volume, bringing down with them, to be deposited on the sea 

 bottom, much mud and debris of all sorts. Thus it has been found 

 that there are extensive areas of mud in St. Helena Bay into which 

 the Berg Eiver opens, at St. Sebastian Bay near the mouth of the 

 Breede Eiver, at Mqssel Bay near the mouth of the Gouritz Eiver, 

 and at Bird Island near the Sundays Eiver. Another feature of the 

 sea bottom is a deposit of a totally different character and origin. It 

 has been found on the west coast from St. Helena Bay to Cape 

 Point, and from thence over the western side of the Agulhas 

 bank, but not beyond on the eastern side of the bank, nor on the 

 eastern side of South Africa. This is a kind of green mud or sand, 

 apparently of organic origin. 



Such are the leading features of the environment of the marine 

 fauna. We may now proceed to consider briefly, and by means 

 of a few examples the co-ordinate modifications found in the 

 forms of animal life themselves. In the trawling operations 

 of the Government steamer exceptional opportunity was afforded 

 of obtaining information as to the kind and distribution of 

 the flat fishes which are in our waters, and to these we shall 

 first direct attention. Trawling operations were first commenced 



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