324 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



All the figures are percentages. The soft bodies only 

 of the lobster, crab, oysters and mussels are included in 

 the above table, the exoskeleton of chitin, or shell, being, 

 as the case may be, omitted. 



Brandt (7) has given a graphic representation of the 

 chemical analysis of 11 plankton catches (fig. 8, p. 325). 



A shows the volume of the catch after it has stood for 

 24 hours. B shows the dry weight of the same. In C the 

 dry weight of the different constituents of the plankton 

 are given. The Diatoms are represented by the clear 

 spaces, the Peridinese by the black, Copepoda obliquely 

 lined, and the remaining organisms dotted. D gives the 

 results of the chemical analysis, the dotted spaces repre- 

 sent the amount of albumen present, the black represents 

 the fat, the horizontally lined the carbohydrates, the clear 

 spaces the silica, and the obliquely striated the other ash. 

 A glance at the figure shows how great an influence the 

 Diatoms exert on the volume results as compared with the 

 weight results. (Vide March, April and September, 

 1893). In spite of the enormous volume of the catch 

 during these three months, the amount of dry organic 

 substance remains small. In March, 1893, the volume 

 has been graphically represented as three times as broad 

 as the others, otherwise it would have had to be made 

 three times as high. 



The first three catches have a large quantity of 

 Ceratium, and are therefore very rich in carbohydrates. 

 The 6th and 7th catches are very rich in Diatoms, and 

 hence contain a large quantity of ash, a fair amount of 

 fat, and relatively little carbohydrate. The 10th catch, 

 which in addition to a large number of Diatoms, contains 

 also many Ceratia, is somewhat intermediate to the other 

 catches. The plankton catches in summer (May and 

 August, 1893) are seen to be made up in dry weight of 



