244 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



four such passages, two of which were made about the 

 time of the anuual minimum of temperature, and two 

 about the time when the sea temperature was rising to the 

 maximum. The means were: — February 15, 5'4°; 

 March 16, 5'06°; May 19, 9'4°; and June 25, 12'37°. In 

 February and March the temperature rises on the whole 

 during the passage from Morecambe Bay to Anglesey, 

 but in June and May it falls. The points on the diagram 

 represent the actual deviations from the means at each 

 spot on the line traversed when temperature observations 

 were made. I have drawn the curve smoothly through 

 the actual points, since it is likely that the temperature 

 change was a gradual and continuous one, and that the 

 observations themselves had no significant error. 



This difference in sea temperature between Anglesey 

 and Morecambe Bay is due not only to the inflow of water 

 round the former island, but also to the great effect of the 

 extensive area of sandbanks in Morecambe Bay. On the 

 4th May, 1909, I made a series of observations of tem- 

 perature in the water of the shallow gutters and pools 

 left by the ebb-tide on the sands immediately to the North 

 and East of Boa Island, in the Barrow Channel. The 

 lowest temperature was 14'2°, and the highest was 17'2°. 

 At about the same time the water in the fairway of 

 Barrow Channel varied from 8'5° to 8'9°, and outside, in 

 a line between the South end of Walney Island and 

 Fleetwood similar readings were taken. At the end of 

 July the temperature in the same place on the sands was 

 as high as 20*5°, while midway across the mouth of 

 Morecambe Bay it did not exceed 16°. It is quite evident 

 that the tidal stream surging backwards and forwards 

 over these sands must influence the temperature of the 

 water out from the land to a very considerable degree. 



