MARINE BIOLOGICAL STATION AT PORT ERIN. 61 
the above, which he has scen in proof:—‘ A slight but 
definite reduction in alkalinity was found in the water 
from the Aquarium outflow, produced during the passage 
of water through the tanks. This emphasises the fact 
that in an Aquarium such as that at Port Erin, where 
water is only allowed to circulate once through the tanks, 
natural conditions are much better approximated than in 
Aquaria where the same water.is pumped again and again 
through the circulation, thus steadily diminishing in 
alkalinity with each passage through the tanks. Port 
Hrin enjoys nearly unique advantages in this respect, the 
water being naturally so clear that there is no need for a 
large storage and precipitation tank.” 
PLANKTON INVESTIGATIONS AT‘ Port Erin. 
In continuation of the work reported upon last year, 
Mr. Andrew Scott and I published in the ‘ Lancashire 
Sea-Fisheries Report,” in May, 1908, a full and detailed 
account of the investigation of nearly 900 gatherings 
taken in the year 1907 in the northern portion of the 
Irish Sea, and of which about 650 are from a limited 
area in the immediate neighbourhood of Port Hrin. At 
the south end of the Isle of Man, where these gatherings 
were taken, there are very important fishing grounds, 
which are frequented by trawlers from Lancashire and 
from Ireland, as well as by the Manx fishermen. This, 
as well as the circumstances that we have there, within a 
few miles, a sheltered sandy bay, an exposed rocky coast, 
a narrow strait through which strong tides run, and an area 
of open sea with depths reaching to 70-80 fathoms, has led 
me to consider Port Krin a very suitable locality for a 
thoroughly exhaustive or intensive study of the Marine 
Plankton. I propose to give here a short summary of 
