MARIXE BIOLOGICAL STATION AT PORT ERIK. 



37 



May 2btJi. — Diatoms much less numerous. Fine net 

 had onh^ about one-tenth, or less, of the gatherings on 

 19th (no obvious change in weather conditions). 



All the above large catches of Diatoms consisted 

 almost entirely of Chaetoceias. It was not until a week 

 later that RJiizosolenia (fig. 13) made its appearance. It 

 reached its maximum early in June, and then gradually 

 died off. By the beginning of July the Diatoms had 

 practically disappeared. 











Fig. 13. Diatom Plankton, consisting 

 mainly of Rhizosolenia semisjnna. 



Fig. 14. Copejaod Plankton, consisting 

 M'holly of Galanus lielgolandicus. 



I insert here a short list just received from Mr. 

 A. Scott, giving the quantity of plankton and his 

 estimate of the total number of Diatoms present in each 



