387 
TaBLe VI 
Showing oxygen in c.c. per liter and per cent. of saturation on fish breeding- 
grounds, 1919-20: Round Prairie, carp breeding-grounds; Warners Cut, bass 
breeding-grounds; Hickory Creek, a typical unpolluted stream; ponds at the 
head of Lake Michigan. 
é July 16| Sept. 4 |Nov. 28 Apr. 2 June 3 Mean 
Locality hs oe te aed AS) oS PSE he a ce ec 2 
e.c.| % | ¢ c.| % |\c. c.| %| ce|% | «| % ¢.c.| % 
‘ | | | 
Round Prairie..|9.75| 12 ary | dry | 5.5 584.1 52 |4.6*| 71*| 3.45| 44 
Warner’s Cut... |8.0 |150| dry | dry |9.2|}95/5.4 TAVIS NCD ed ice ein Maan ng ism fal 05) 
Illinois River... | 3.7 61 AO [ease ate 6.0 77 |4.8 | 78 4.2 64 
Pon dls 7.53 20% Milbea cit nes PAA a com eS OA ds ae | alee w | 0, 9) | 110 9.8 | 146 
Pond Vescss5. «6 wee fee. | 7.3] 135/7.5| 88|8.1*| 183*| 4.5 70 6.4 98 
ond! MT, Wes <2] os a) ses LT 38')) (330 8.1, Sole ee ee le be (120) Wate LS tse 
Pond XIV ..... veee| | 12.4] 230) 6.8) 81 Sere | Ooae | kta 8.7 | 141 
* Not included in the mean. i 
7 High on-shore wind prevented our reaching this station. The strong waves should 
have given a 100% saturation. 
Tas_e VII 
Showing the hydrogen ion concentration in different fish-waters, July, 1919, 
to June, 1920. 
Bottom Top 
iJ~) ao (=) a 
Locality crs (oar od Fa a ea Be | olde 
PlBIS/ 8/8 (a /2/8|8) 8/8 la 
Sheds [pepe ts a la] 4/4 +s 
Dake | Michisans seek <<8] od svee[c ee, fice |) s iar 7.9|-7.917.917.8 |'7.9|7.9 
Round Prairie... |7.15| dry|7.3)7.3|7.3-|7.27]7.2| dry |7.3/7.4 |7.6|7.4 
Warner’s Cut.../|7.95| dry |7.9/7.4 7.7518.2| dry |7.9/7.5 7.8 
Ill. Riv., Jefferson 
hice EAU AMES 12 1| CoB | i0r< cu fze are POPS Nicaea lef GNC I ig Ge: ik PRS Cal i fey dT) 
BOOM EDV Ole rer itn Lee leceici a [Mebetes[ oer aioivetore Leet UO Ce Oi oct s, | Ceo Tas DO 
Hickory Cr...... Tey MeO aCe Dike At TeSth VoOr Nh led | aS beD | GO | 687.7 
Rand Tet ots. % 6 Me OD hate MuleOiese Tesla dre ol Ce Gi ukeS | tO) | soe | hod | 1.8 
L2G) (GL Sheree RIE I So Sa |i Gea fae AP AS (57 OS Peay ey GS bl Nr GP Bir QL 3 
Pond VII, W.....|8.5 | 7.85} 7.91). TA \ 7.9 18.2) 8.2)-7.9)...:. | 7.9'|8.05, 
Pond XIV ...... 7.85|7.5 |7.6} eB ah sO | Geo-| S224) 09) GE ORY 
Pond. Vit, 6.8 |6.8 |7.3 OAc Nh fe Mod Ue i 2 an a | 7.3 F 7.7|7.4 
* Not included in the mean. 
The series of ponds was quite fully studied in 1909-1911 (see Bio- 
logical Bulletin, volumes 21 and 22). 
Pond I at that time contained bass, sunfish, and perch. Bare sand 
breeding-bottom. 
Pond V contained perch and chub-suckers. Bare sand breeding- 
bottom. 
