452 D. J. SCOUR FIE LB [june 



localities representing different types of environment. These were at 

 first made by a modification of the Hensen-Apstein methods, but as the 

 work proceeded several important alterations were introduced, such as the 

 employment of a pump for the collection of the plankton material, 

 and of a centrifuge for its rapid deposition. Numerous painstaking 

 experiments have also been made with a view to determine and 

 correct the errors in quantitative plankton methods in general, and all 

 workers in this field are indebted to Dr. C. A. Kofoid, who has had 

 charge of this department, for the light which he has thrown on the 

 subject (9 and 10). Unfortunately, owing to the large amount of 

 labour involved in working out the collections, and the small staff 

 available for the purpose, none of the results of the actual work on 

 the plankton have yet been published. When they do appear, how- 

 ever, they can hardly fail to be of the highest scientific value. 



The aquatic insects have received a large share of attention at the 

 Illinois Biological Station, and it has been the special endeavour of 

 those working at these forms to get full particulars of the life-histories 

 of the species, both by constant collecting and by breeding. In this 

 way a large amount of information has been collected on the immature 

 stages of over two hundred different species, the great majority of 

 which had not been previously known (5). 



Besides the insects many other groups of animals have been care- 

 fully and profitably studied, as is abundantly clear from actual publica- 

 tions dealing with the Protozoa and Eotifera (6 and 7), Oligochaeta 

 (21 and 22), Ostracoda (20), and Copepoda (3, 18 and 19). Materials 

 have also been accumulated for treatises on several other important 

 groups. 



In addition to the special researches carried on by the station 

 staff and visitors, an attempt was made last year to run a summer 

 school of biology in connection with the station, with regular courses 

 in botany and zoology. Although hardly so well attended as was 

 anticipated, the scheme was thoroughly successful (4, 1897-8). Such 

 a school should be of the greatest practical importance in the training 

 of biological students, and it is to be hoped that when the exceptional 

 advantages offered by the Illinois Biological Station are better known 

 there will be no need to complain on the score of attendance. 



The year after the establishment of the Illinois station, i.e., in 

 1895, Professor C. H. Eigenmann was enabled, with the aid of the 

 Indiana University, to open a biological station on the shores of 

 Turkey Lake in Indiana. The main scientific object of this station has 

 been the study of variation, and to this end a small lake, within which the 

 influences of environment are presumably reduced to a minimum, was 

 purposely selected. During the four years since the starting of the 

 station a large amount of material has been obtained to illustrate 

 such points as the annual variation, the birth mean, and the effect of 

 selective destruction, but only a portion of this has yet been thoroughly 



