SEA-FISHERIES LABORATORY. 153 



Unusual specimens, or anything not recognised 

 should always -be preserved for examination in 

 the Liverpool Laboratory. 



II. — " Plankton" (or Tow-Net) Collections. 

 " Tow-nettings should be taken along with every drag 

 of the fish trawl. One haul with a bottom and one with 

 a surface net should be made on each occasion. The 

 collections should be at once preserved in formaline 

 solution, and sent to the Liverpool Laboratory as soon as 

 convenient after landing. Extra tow-nettings should be 

 taken as frequently as possible. All such observations 

 on the floating life of the sea (which includes the eggs 

 and the microscopic food of many fishes) are most useful. 

 Even short hauls of half-an-hour's duration, taken twice 

 a week, will probably suffice to give a fairly accurate idea 

 of the movements of the Plankton in the District. 



III. — Physical Observations . 



" (a) Sea Temperatures. — Surface and bottom obser- 

 vations should be taken at the beginning and 

 end of each drag. Bottom temperatures 

 should be taken with a reversing thermometer. 



" (b) Specific Gravity of the Sea Water. — Surface 

 and bottom observations should be taken at 

 the beginning and end of each drag. Bottom 

 observations should be made on samples of the 

 bottom water, taken with a Mill's bottle. 



" (c) Air Temperature. — One observation at the 

 beginning of each drag should be taken for 

 comparison with the sea temperature. 



" (d) Barometric Pressure. — One observation taken 

 at the beginning of each drag is sufficient. 



" (e) Transparency of the Sea Water. — One obser- 

 vation should be taken at the beginning of 



