260 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Head during the ebb, and towards the south past Port 
Krin when flowing, and will thus no doubt be somewhat 
affected both in direction and amount. On the other 
hand, the westerly and north-westerly winds (4) blow on 
shore, bringing in the surface plankton from further out, 
and possibly allowing deeper layers of water and plankton 
to well up out in the middle of the channel where the 
depth is relatively great. The southerly and south- 
westerly winds (3) blow up channel, frequently with a 
heavy sea, and would tend to bring the plankton from 
St. George’s Channel into our district. On reaching the 
shallower irregular rocky bottom off the south end of the 
Isle of Man, where the tides run strong, this water may 
very probably be so diverted and churned up as to cause 
vertical movements, bringing deeper layers to the surface 
in the neighbourhood of the Calf Island. It is here that, 
on various occasions, we have obtained unusually large 
catches of zoo-plankton. The last of our groups of winds, 
the north-easterly, are probably those that have least 
effect on the water and its contained plankton off Port 
Krin. Any effect will probably be much the same as 
that caused by the easterly group, but less in amount— 
and blowing off-shore from the south end of the island 
may cause deeper layers of water to rise to the surface 
close to land. Here again any such movements will 
probably be modified by the strong tides running round 
the Calf Island. 
In figs. 4 and 5 the occurrence and intensity of 
these four groups of prevalent winds are shown as lines 
of varying length on each side of two datum axes for 
each month in the years 1907 and 1908, so that their 
proportional distribution may be traced day by day through 
the months—each recorded observation being plotted. The 
upper datum axis for each month has from N. to H.N.E. 
