PLANKTON 243 



plankton. On one occasion in mid-ocean I encountered a 



good example of a swarm of a very minute organism so 



abundant as to colour the water. In the Southern Ocean, 



between the Cape of Good Hope and Australia, the sea was 



noticed one afternoon to be blood-red in the curl of the 



waves where the sunlight shone through. I pointed it out 



to several members of the British Association party on 



board, and all agreed that it was most striking. My tap-net 



a little later showed that the colour was due to a minute 



red Peridinian, which must have been present in enormous 



profusion over a limited area in the open sea where there 



was no recognized current carrying special conditions— and 



cases are on record of swarms of this or an allied form not 



only colouring the sea locally, but also causing such a 



pollution of the water as to result in widespread death of 



larger marine animals so as to cause a nuisance when cast 



up on the Australian coasts. In the recent literature of 



the subject there are many other similar cases of marked 



irregularity of even the more minute plankton in the open 



ocean, such as Ove Paulsen's observation that the sea 



to the east of Iceland in July was blood-red for days from 



the presence of Mesodinium pulex, and also his record of 



very unequal distribution in the open Atlantic Ocean near 



the Faroe Bank — the quantity of plankton being very 



much greater in one haul than in the previous one. But 



to my mind the chart-diagrams of the quantitative plank- 



tologists themselves tell in the same direction ; for example, 



the one giving the results of the Plankton Expedition in 



the Atlantic shows a very marked irregularity, not only as 



between arctic, temperate, and tropical waters, but also 



almost day by day in most parts of the ocean traversed. 



In all these cases, no doubt it may be said the plankton 

 results were different because the conditions were not 

 similar ; but it is surely not justifiable to say that in the 

 open sea the plankton must be evenly distributed because 

 the conditions are constant over large areas, and then, 



