16 ILLINOIS ACADEMY OF SCIENCE 



A careful study of the chemical relations of fishes has been 

 made by Mr. M. M. Wells, who has found that Illinois fresh- 

 water fishes are very sensitive to acid and alkaline conditions 

 of the water. Fishes avoid alkaline and neutral waters, and 

 select those slightly acid with carbon dioxide, but avoid waters 

 containing large amounts of acid — conditions particularly 

 detrimental to the young. Mr. Wells has also found that 

 fishes are least resistant to detrimental conditions during the 

 breeding season, some species dying at once when taken from 

 water at this time. 



Dr. H. S. Pepoon has been completing his flora of the Chi- 

 cago area, now practically ready for the printer, and has been 

 working up also his plant collections from the driftless area 

 in northwestern Illinois, in which he has found many new- 

 forms and extensions of plant localities. His Jo Daviess 

 county list now contains nearly a thousand species, several 

 of which are not found in Gray's Manual. 



Mr. F. C. Baker has continued his studies of the ecological 

 features of the basin of the glacial Lake Michigan. Shallow- 

 water and deep-water faunas have been found in the new 

 Calumet-Sag Channel, now under construction. A section 

 thirty feet deep near Worth shows the same fauna which was 

 observed by Baker in the North Shore Channel at Bowman- 

 ville, as reported in Volume IV of the Academy Transac- 

 tions. A Unio species especially charactceristic, Unio crassi- 

 deus, was present in great numbers. Air. Baker finds evidence 

 that a rich Unio fauna migrated up the Des Plaines during the 

 Calumet stage and became well established by the time the 

 water had lowered to the Toleston level. The fauna of the 

 Algonquin and Nipissing stations is large and varied, the 

 species represented indicating the fluctuations in depth as the 

 level of the water rose and fell. A report covering the life 

 of the Pleistocene, as recorded in both post-glacial and inter- 

 glacial deposits, is now nearly finished and ready for publica- 

 tion. 



The ecological work of the Illinois State Laboratory of 

 Natural History has been substantially in continuance and 

 verification of the Illinois River work of 1914, special atten- 

 tion being paid, however, to collections of the stomachs of 

 fishes for an elaborate study of the food of different species 

 in different situations. Materials were also collected for food 

 studies of aquatic invertebrates living on the bottom. Many 

 dredge collections were obtained from the Illinois River and 

 connected lakes; and a special biological examination of Fox 



