MAECH 9, 1900.] 



SCIENCE. 



875 



greatest depths, a fauna, not very abundant 

 to be sure, but of great interest because of 

 the strange peculiarities of some of the 

 forms. With others I was profoundly in- 

 terested in this work, and it lead me to con- 

 jecture whether there was not a field for in- 

 vestigation in the deeper waters of our 

 lakes. At that time very little had been 

 done in the way of any systematic study of 

 the deeper waters of the lakes. I think the 

 only extensive work on the subject was 

 Forel's ' La faune profonde des lacs Su- 

 isses,' published in 1885. Professor Forel 

 had begun his researches on the deep water 

 fauna of Lake Leman in 1869, and had pub- 

 lished various notices in the intervening 

 years. In this country, so far as I know, 

 the first publication jn regard to the deep 

 water fauna of lakes was in the first vol- 

 ume of the Traiisaetions of the Wisconsin 

 Academy, in a paper by Dr. Hoy, of Ra- 

 cine. He detailed how he had become in- 

 terested in the food of the whitefish, and 

 had examined their stomachs, finding cer- 

 tain animals that seemed new to science. 

 A company was made up for a dredging ex- 

 pedition consisting of Dr. Hoy, Dr. Lap- 

 ham, Professor Stimpson, Professor An- 

 drews and Mr. Blatchford, and put in a 

 day's work dredging on Lake Michigan in 

 June, 1870. The result was the collection 

 of a considerable number of animals. Es- 

 pecial importance was attached to the dis- 

 covery of a Triglopsis and a Mysis, as they are 

 marine genera, and their presence was sup- 

 posed to indicate a former direct connec- 

 tion of Lake Michigan with the ocean. 



In 1874 Professor Smith published a 

 paper on the ' Invertebrate Fauna of Lake 

 Superior,' reporting the existence of the 

 same Crustacea in Lake Superior which Dr. 

 Hoy had found in Lake Michigan. The 

 Mysis there, however, occurs in somewhat 

 shallow water as well as in the greater 

 depths. In both lakes it forms an impor- 

 tant — perhaps the most important — constit- 



uent of the food of the white fish and lake 

 trout. As I was located near a lake of 

 considerable depth, a depth reputed to be 

 anywhere between 400 feet and infinity, it 

 occurred to me that I had an opportunity 

 to carry out similar researches. 



My own work on lakes, then, originated 

 in a desire to know more about the abyssal 

 animals. I soon found, however, that the 

 problem was a serious and complicated 

 one, involving a complete faunistic study 

 of the lake. I was fortunate in finding 

 on the bottom of Green Lake the same 

 Mysis, which makes its home in Lake Mich- 

 igan. These animals have not been defi- 

 nitely reported from any other lake in 

 the United States, although Mysis is said 

 to live in a lake in Ifew York connected 

 with the St. Lawrence. Here was a pretty 

 problem in animal distribution. How did 

 these animals make their way into Green 

 Lake ? Was it by way of the Great Lakes, 

 or did they come at some time by a connec- 

 tion through the Mississippi Valley? I 

 could not tell, and I cannot to-day, for it 

 becomes a problem for the geologist rather 

 than the zoologist. With this as a start- 

 ing point I attacked the problem of lake 

 faunae, and the battle is still in progress 

 with no indications of a conclusion of hostil- 

 ities for many years to come. 



During the decade in which I have been 

 interested in limnology there has been a 

 very considerable advance in our knowl- 

 edge of the subject, and it will be my at- 

 tempt to-night to summarize this knowledge, 

 and make as clear a statement as I can in 

 the brief time at my disposal of what is 

 now known of the fauna and flora of fresh 

 water lakes. Eussell, in his work on North 

 American Lakes, enumerates ten agencies 

 which, acting separately or in combination, 

 may produce lakes. So far as our Wiscon- 

 sin lakes are concerned, the most important 

 of these agencies is glacial action. Most of 

 our lakes are simply the depressions caused 



