178 



The warm Agulhas Current flows along the east coast of 

 South Africa and east of the Agulhas Bank with a variable 

 velocity, strongest in the summer months, especially in Feb- 

 ruary. As a rule the average velocity amounts to about 2 knots ; 

 in the winter, especially in July, the velocity diminishes con- 

 siderably, and the cold water from the Westwind Drift 

 repels and permeates the current. 



South-east of the Agulhas Bank the waters of the Agulhas 

 Current become deflected and mixed with the water of the 

 Westwind Drift, which moves eastwards, in the wintei months 

 and April with a velocity of about i-i"25 knots. 



The mixed water of the Agulhas Current and ihe Westwind 

 Drift continues towards the east with a velocity of i"5-2 knots. 

 During the passage it sends a branch along the west coast of 

 Australia, and a very mighty one, when it meets the south end 

 of America, or the north going Humboldt Current. This may 

 explam the fact that I found in the samples collected east of 

 Natal a very considerable number of the copepoda discovered 

 by Giesbrecht in the depths west of South America. 



The currents over the Agulhas Bank are as a rule weak and 

 variable. Between Cape Town and Cape Agulhas a current 

 sets in in an E.S.E. direction with a velocity of one mile per 

 hour. Along the south coast from Cape Agulhas to about 

 27° E. an eastward running current has been observed. Thus 

 the water south of the Cape Colony is derived, at least to a great 

 extent, from the west, that is from the origin of the northwards 

 running Benguela Current. The latter is to be considered as 

 a branch of the Westwind Drift, more or less mixed with wateis 

 from the Brazil Current, the continuation of which it touches 

 during the passage from the South of America. 



It might be expected that the waters on the Agulhac Bank 

 would possess a kind of plankton different from that of the 

 waters East of South Africa. This will be proved by the 

 followmg account. It will be found that of the copepoda 

 found south and west of the Cape Colony a considerable num- 

 ber also occur in the northern hemisphere, north of a line 

 traced from the Newfoundland Banks to the Azores and the 

 Cape Verde Islands, some so far to the north that they pass 

 through the Faroe Channel and reach the coasts of Scandi- 

 navia. There is thus a strong probability that the hvpothesis 1 

 have enunciated, that the waters of the temperate Atlantic in the 

 northern hemisphere originate not from the Gulf Stream, but 

 from the Benguela Current, which is supposed to pass as an 

 under-current below the waters of the tropical Atlantic. 



In order that the reader may judge of this question I have 

 compiled from the literature an account of the geographical 

 distribution of all copepoda found in the South African Seas. 



I will in the following treat first of the copepoda of the west 

 coast, then of the south coast and, finally, of the east coast. 



