SIXTH ANNUAL MEETING |9 



tion of Dr. C. C. Adams, of this committee, and his paper on 

 this subject is in the hands of the director of the State Lab- 

 oratory for similar publication. The Charleston area is be- 

 ing studied, as heretofore, by Dr. E. X. Transeau and Mr. 

 T. L. Hankinson. of the Eastern Illinois State Normal School. 

 They. too:ether with Dr. Adams, of the U. of 111., are pre- 

 paring a report upon a cooperative work done in this area 

 three years ago. The plant ecology of the two northwestern 

 counties mentioned is being studied by Dr. Pepoon : and the 

 whole system of life of the Illinois River and the waters of 

 its bottom-lands, together with that of the Des Plaines River 

 and the sanitary canal, is being continuously studied by Dr. 

 S. A. Forbes and Mr. R. E. Richardson, the latter in charge 

 of field operations with headquarters at Havana. 



Dr. Shelford reports the preparation of a general treatise 

 on the ecology of the region about the head of Lake ^lichi- 

 gan. soon to be published, in" a semi-popular form, under the 

 auspices of the Geographical Society of Chicago. Additional 

 data has been presented in a series of papers printed in the 

 Biological Bulletin, in which the following facts have been 

 brought out : Fishes are sensitive to hydrographic conditions, 

 and thus have definite arangements in comparable streams. 

 ( Streams flowing into Lake Michigan, between Glencoe and 

 the Wisconsin line, are comparable in hydrographic condi- 

 tions, their differences being due to differences in physio- 

 graphic age. The head-waters of the oldest streams contain 

 only species of fishes found in the smallest streams. Other 

 species are arranged in the same order of succession in all the 

 streams, those nearest the mouths of the largest streams be- 

 ing absent from the next smaller streams.) etc. A series of 

 ponds at the head of Lake Michigan, arranged in the order 

 of ecological age as shown by the amount of humus, the 

 character of the vegetation, and the physiographic history, are 

 shown to contain fishes which have a definite arrangement 

 in these ponds (correlated with (a) the presence or absence 

 of the kind of bottom prefered by the species in breeding; (b) 

 with the amount of oxygen and carbon dioxide in solution ; 

 and (c) with the amount of humus and vegetation present. 

 Fishes may be few where their food supply is most abundant ; 

 and the smaller food supply has been shown not to be due to 

 tlie presence of the fishes). 



A study of the dilTerent stages of forest development on 

 sand has shown that the distribution of animals is correlated 

 with the differences in the evaporating power of the air. 



A study has been made of the seasonal succession in a 

 temporary spring pond and on the low prairie vegetation of 



