[ 555 ] 



Notes on Experiments in the Keeping of Plankton 

 Animals under Artificial Conditions. 



By 

 L. R. Crawshay, M.A. 



TABLE OF CONTENTS. 



PAGE 



Introduction ............. 555 



The experiments ............ 559 



Results obtained in Positions A and B . . . . . . . . ,, 



Zoaeae . . . . . . . , . . .' . . >» 



Calanus finmarchicus . . . . . . . . . . >i 



Temora longicornis ........... 560 



Anomalocera Patersoni .......... 561 



Acartia sp. . . . . . . . . . . . . >» 



Young Calanoids ..........•»» 



General ............. 562 



Special experiment in Position A . . . . . . . • »> 



Results obtained in Position C ........ . 56J- 



Pseudocalanus elongatus .......... 564 



Calanus finmarchicus .......... 565. 



Acartia sp. ........... . 566 



A comparison of C results with A and B results . . . . . . ,, 



General remarks ............ 568 



On Diatom growth in the experiments ........ 570 



The influence of some Bacteria on the experiments, and their destruction . . 572 



Introduction. 



The experiments referred to in the following pages were carried out b^ 

 the wish of the Director at the Plymouth Laboratory, between June, 

 1912, and February, 1913. They were undertaken with a view to keep- 

 ing under observation some of the smaller zooplankton, and particularly 

 the Copepoda, in order that they might be followed through the 

 different stages of their life cycle. After a long series of disappointing 

 results, the experiments were unavoidably interrupted at a time when 

 apparently the chief obstacles to success had been located and largely 

 overcome. 



Continued observation of these small animals has only in the last few 

 years been rendered certainly possible by the work of Dr. Allen on the 

 culture of the marine Diatoms, which form the chief food supply of the 

 great majority of them, and it is not surprising that until the problem of 

 obtaining and keeping a suitable food culture was settled, attempts to keefv 



