4OO WILL SCOTT. 



7. The plankton is composed of epigean forms and is derived 

 from ponds in such sink-holes as have an opening above their 

 lowest points. 



8. Temporal distribution of the plankton depends upon three 

 principal factors, the production of the plankton in the pools, 

 excessive rainfall, and the ability of the planktons to withstand 

 cave conditions. 



9. At ordinary stages of the stream more plankton occurs in 

 the upper part of the cave than in the lower part. 



10. Some of the planktonts feed and reproduce in the cave, 

 but these processes are more or less inhibited. 



11. The plankton is not a part of the permanent cave fauna 

 but is essentially a pond fauna accidentally carried into the cave. 

 It is either carried through the cave or perishes in it. 



LIST OF SPECIES. 1 



PROTOZOA. 



Arcella vulgaris Enrenberg. 



Difflugia globosa Dujardin. 



D. pyriformis Perty. 



D. lobostoina Leidy. 



D. acuininata Ehrenberg. 



Euglena sp. 



ARTHROPODA. 



Cyclops bicuspidatus Claus. 

 C. prasimis Fischer. 

 C. viridus J urine. 

 C. serrulatits Fischer. 

 C. edax Forbes. 

 Canthocamptus sp. 

 Daphnia pnlex DeGeer. 

 CiriodapJmia consors Birge. 

 Bosmina boJicinica Hellick. (?) 

 B. cornuta J urine. 

 Cydorus splicericus Mueller. 



1 Diatoms were taken occasionally. The collections sometimes contained spiders 

 which doubtless had fallen from the walls of the cave. One round worm and two 

 segmented worms were observed during the year. 



