384 
4- To 7-roor Zone, 1915 
NUMBERS PER SQUARE YARD, AVERAGE 
Chillicothe to Mossville 30.8 200.8 68.7 299.8 | 16 
Peoria Narrows to foot of 
Peoria Lake 53.0 167.5 52.5 373.5 4 
Average | ayes | Riacore | a Yelate | 314.4 | 20 
tion opposite (345.1 pounds), although numbers per unit area were about 
the same, the Sphaeriidae and smaller Gastropoda making up over 50 
per cent. of the average in weight and the insect larvae, worms, and 
Crustacea over 7 per cent. as compared with much smaller ratios in the 
channel collections. 
The average 4- to 7-foot zone* valuation (259.4 pounds per acre) 
was about two and a half times that of the 1- to 3-foot zone (108.4 
pounds), and about 25 per cent. under the average channel valuation 
(345.1 pounds). The larger snails (Viviparidae principally), while not 
relatively so abundant as in the channel collections, made up a noticeably 
larger portion (64.6 per cent.) of the totals by weight than was the case 
in the 1- to 3-foot zone. 
Tables summarizing these comparisons‘ of the channel and shore 
zone averages follow. Further details concerning separate species and 
families included in the valuations are found in the detailed tables at end. 
‘ 
Borrom Fauna, CHILLICOTHE TO Foor or PrortA Lake,* 1915 
SUMMARY y 
Channel, 4- to 7-foot | 1- to 3-foot 
12 zone, 20 zone, 10 
collections collections collections 
Average number per square yard 234.8 314.6 233.7 
Average pounds per acre 345.1 ' 259.4 108.4 
Per cent. (by weight) 
Viviparidae and Pleuroceridae 84.9 64.6 41.3 
Per cent. (by weight) 
Sphaeriidae and small Gastropoda 14.0 30.9 51.6 
Per cent. (by weight) 
Insects, worms, Crustacea 11 4.5 71 
* No collections at Peoria Narrows. 
* Channel collections at Peoria Narrows omitted. 
to 3-foot or 4- to 7-foot zone at that station. 
No collections taken in 1- 
