No. 631] 



ANIMAL LIFE AXD SEWAGE 



155 



river at Charlotte near the mouth of the river. This, 

 however, does not enter into the present discussion. It 

 has not been possible to ascertain the amount of sewage 

 entering the river during the period of maximum dis- 

 charge, but at the present time the approximate quantity 

 of sewage discharged is one-eighth cubic foot per second 

 (data from Eochester engineering department). This 

 is a comparatively small amount which apparently has 

 little or no effect on the animal life in the river. On the 

 contrary, it may provide food for some organisms. 



Sewage was turned into the Genesee Eiver about the 

 year 1820. Collections of molluscan life were made in 

 July, 1897, and nine species were obtained, as noted 

 below: 



Musculium transversum Physa gyrina 

 Musculium partumeium Physa sayii 

 Bythinia tentaculata Physa heterostropha 



Galba catascopium Galba caper at a (rare) 



Planorbis trivolvis 

 Previously, in 1892-1895, collections had been made 

 which included about the same species as noted above. 

 Individuals were notably abundant, thickly covering the 

 rocks and the shore. At the time the above mollusks were 

 collected it was noted that the sewage was increasing in 

 volume and pollution was becoming more noticeable. It 

 was predicted at this time that in a few years the fauna 

 would be exterminated bv the foulness of the water. 



The river was visited and examined in 1898, 1900, 1901, 

 1904-1907, 1908, 1910, 1913, 1915-1917, and 1919. 4 Each 

 year it was noted that the pollution of the water was 

 rapidly increasing. In 1907, the water-breathing mol- 

 lusks, Musculium and Bythinia, had succumbed and none 

 could be found. The air-breathers, Galba, Planorbis, 

 Physa, still held out, though reduced in number of indi- 



«See the following papers by the -"ter: -The Molluscan Fauna of 



