FRESH WATER IJFE. 13 



table all that time, stagnant, no water being added except 

 about four times to make up for evaporation, and there was no 

 vegetable matter in it to sustain animal life. The following 

 were found: Innumerable empty frustacles of different diatom- 

 acese. 



We can now compare this with a specimen taken from the 

 same place and examined while fresh, Aug. 8th, 1904. 



Desmids. 

 Docidium rectum 4 specimens 



C'losterium Diana? 

 Parvulum 

 '* \'enus 



Acerosum 

 iSubcostatum 

 " Costatum 

 " Strigosum 

 " Maeilentnni 

 Micrasterias radiosa 

 Euastrum Verrucosum 

 Arithrodesmus Octocornis 



Diatoms. 

 Navicula viridis. 



'• dactylus in plenty. 

 Numbers of Nais worms and several specimens of cy- 



cl0|)S. 



This shows quite a difi'erence and p(Mnts out fairly well the 

 different forms that likely perished in the first specimen on 

 account of the stringent conditions, such as impure water and 

 lack of food. 



Specimen No. "2. 



Taken from a running brook Oct. 14, 1903, and examined 

 JNIay 13th, 1904. and subject meanwhile to the same conditions 

 as No. 1. Result: 1 Closterium, green (not moving), 11 Pterod- 

 inre patina?, quite lively. Numerous frustules of different 

 diatoms. Nothing more. 



Compare fresh sjiecimen from same place. September 18th. 



