476 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



town of Conway to some distance above the bridges, there 

 is mussel ground on the channel bottom. Mussels are 

 raked all over the bed of the Estuary on the shaded part, 

 and are picked by hand on the scars. 



The Sewer Outfalls. 



The sewer outfalls are also marked on the chart and 

 the numbers adjoining them indicate the number of 

 people in the area served by the sewers. Above the 

 bridges there are two sewers, one serving a population of 

 about 600 people, and opening on the western side of the 

 river; and the other serving a population of about 1,250 

 people at Llandudno Junction, and opening into a little 

 brook which flows down over the sands to open into the 

 Estuary quite close to the tubular railway bridge. On 

 the western side of the river is a further group of three 

 sewers serving a population of about 2,600 people — that 

 of the town of Conway. Further down, two small sewers 

 serve a group of houses (about 690 people) at the place 

 known as Morfa Parade. On the eastern side of the 

 Estuary there are sewers at Deganwy and Tywyn, 

 serving a population of about 1,600. Thus this part of 

 the Estuary, only about 1\ miles long, and, on the 

 average, about one-third of a mile in width, receives the 

 sewage of a population of about 6,750 persons. Also, 

 above Conway, the sewage from a population of about 

 4,120 persons also drains into the river. 



Bacteriological Analyses. 



I give here an account of recent analyses only ; many 

 more have been made in the past, but all those to which 

 I refer have been made by identical methods, so that all 

 the results are comparative. I take Conway first, as this 

 locality may be regarded as a standard one, with which 

 the others may be compared. 



