382 
Bortom Fauna, CHANNEL, 1915 
NUMBERS PER SQUARE YARD, AVERAGE 
Aue: , Small 
Viviparidae Insects Col- 
and aede worms, Total | lec- 
Pleuroceridae Sphaeriidae Crustacea tions 
Chillicothe—Mossville 88.2 143.7 26.6 258.5 8 
At Peoria Narrows 23.2 1.0 13.3 37.5 3 
Peoria Narrows to foot of 
Peoria Lake 134.5 5.0 48.0 187.5 4 
Average (excepting collec- 
tions at Narrows) 234.8 | 12 
The average valuation of the channel bottom fauna in pounds per 
acre (shells of Mollusca deducted) in this section (285.9 pounds, with 
the Peoria Narrows station included; 345.1 pounds, with Peoria Nar- 
rows omitted) was better than the average (239 pounds) for the 43.7 
miles between Chillicothe and the Copperas Creek dam, but was less 
than one tenth of the channel average between Copperas Creek dam and 
Havana (3,029 pounds per acre), and less than one twentieth of the 
average valuation for the eight miles between Liverpool and Havana in 
1915 (5,180 pounds per acre). The great bulk of the collections, by 
weight (85 per cent.), was made up of the larger snails (Viviparidae and 
Pleuroceridae), and these families together with the Sphaeriidae and 
smaller Gastropoda accounted for about 98 per cent. of the average 
poundage taken. 
Bortom FAauns, CHANNEL, 1915 
POUNDS PER ACRE, AVERAGE 
wees 3 Small | 
Viviparidae | Insects, | Col- 
and er a worms, | Total | lec- 
Pleuroceridae Sphaeriidae| Crustacea tions 
Chillicothe to Mossville 244.1 70.4 api 317.6 8 
At Peoria Narrows 46.3 0.5 2.1 48.9 3 
Peoria Narrows to foot of 
Peoria Lake 391.6 yal 5.6 400.3 4 
Average (including « Nar- 
rows) 2 243.8 38.4 3.5 285.9 15 
Per cent. of total 85.2 13.4 1.4 
Average (excluding Nar- we 
rows) 293.2 47.8 3.9 345.1 12. 
Per cent. of total 84.9 14.0 1.1 | 
