304 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



form must be studied in connection with the explanation 

 in the text. The form contains the results of one of 

 Apstein's investigations (5) on the fresh water plankton of 

 one of the Holstein lakes. Although the form records 

 fresh water organisms, an exactly similar form can be, 

 and is, used for salt water plankton. 



The forms for comparing results of different catches 

 present no special features, and one can easily be devised, 

 so I have not thought it necessary to reproduce one here. 

 At the head of such a form are printed the names of the 

 various organisms captured in the plankton. At the left- 

 hand side are spaces for entering the number and certain 

 particulars regarding the catch. Underneath the head- 

 ing for each organism and opposite the number of the 

 catch are entered numbers giving the total number of 

 organisms for the catch and the number per unit area of 

 surface, so that it becomes easy to compare different 

 catches either taken at the same place at different seasons 

 or at different places. 



With regard to the form, first of all in the top left- 

 hand corner the number, place and date of the catch are 

 noted. For instance, 32a. Dobersdorfer Lake. 20 Sept., 

 1891. The number 32a is recorded in a Journal in which 

 information of a physical character is noted, such as the 

 depth of water, its temperature, the temperature of the 

 air, the direction and force of the wind, as well as the 

 general condition of the catch, and any other information 

 likely to be serviceable. On the form we see vertically 

 and horizontally ruled spaces. Taking the vertical rows, 

 we see on the extreme left the heading, " Kind of investi- 

 gation." Under this heading we enter either dry or moist, 

 according to the nature of the plate on which the 

 enumeration is carried out. As a rule dry plates are only 

 used for the enumeration of Diatoms. Under the second 



