152 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



III. Physical Observations with thermometers, 

 hydrometers, &c. 



/. — Fish and Shrim}> Trawling Observations. 



" (a) Drags should be made under strictly uniform 

 conditions : that is, the same trawl net should 

 always be used, and the drags should be of 

 uniform length and duration, in order that 

 they may 'be as strictly as possible comparable 

 with one another. In addition to the fish 

 trawl, it would be very useful — especially at 

 Stations 1, 2, and 3 — if a haul of the shrimp 

 trawl could also be taken. 



" (b) Every drag should be recorded, irrespective of 

 the numbers of fish caught. A poor haul is 

 just as important for statistical purposes as a 

 successful one. 



" (c) All the fish caught should be measured, and the 

 numbers of each kind and size accurately 

 recorded on a Form similar to the one 

 appended. 



" (d) Two or three individuals of each of the more 

 important kinds of fish — such as plaice, sole, 

 cod, haddock — from every haul should be 

 weighed and measured separately. The 

 ovaries should then be taken out and weighed, 

 and the results recorded on the Form. Any- 

 thing noteworthy in the condition or 

 appearance of the ovaries should also be added. 



" (e) Mention should be made of any unusual fishes 

 or invertebrata taken in the trawl, and also of 

 any special abundance of common things such 

 as star-fishes, crabs, molluscs, jelly-fish, 

 zoophytes, worms, or other fish food. 



