ON THE CYCLOPUXE AND CALANID^E OF LAKE ST 

 CLAIR, LAKE MICHIGAN, AND CERTAIN OF 

 THE INLAND LAKES OF MICHIGAN. 



From the standpoint of the pisciculturist, perhaps no class of animals 

 outside the fishes themselves is so important and interesting as the ento- 

 anostraca. It is a well known fact that these minute Crustacea form the 

 entire food material of the young of some of our most important food 

 fishes, and in many cases form a large part of the food of the adults. 



They are universally distributed. Every stream, lake, pond, and pool 

 has its population of these minute creatures. Moreover they are present 

 in some places in enormous numbers. In the deeper waters of our lakes 

 the surface waters to a depth of about thirty feet fairly swarm with cope- 

 pods. In limnetic collections there are always present some Cladocera, 

 but the great bulk of the material in any lake will consist of two or three 

 species of Diaptomus and as many of Cyclops. 



Inasmuch as the occurrence and abundance of animals is largely depen- 

 dent on their food supply, it will be seen that an accurate and thorough 

 knowledge of entomostraca is of fundamental importance, if we would 

 have an exact knowledge of the conditions controlling our fish. 



The material on which this paper is based was obtained from the 

 following sources. 



1. Collections made by Professor Reighard in certain lakes in southern 

 Michigan in the summers of 1891 and 1893. 



2. Collections made by Professor Reighard in the northern part of 

 Lake Michigan in the spring of 1893. 



3. Collections made by Professor Reighard during the biological exam- 

 ination of Lake St. Clair in the summer of 1893. This involved a very 

 large number of collections in the months of July and August, and its 

 results probably give us a very accurate knowledge of the copepod fauna 

 of Lake St. Clair in the summer season. In connection with this work a 

 few collections were also made in the Detroit river and in Lake Erie. 



4. Collections made in July and August 1894 in connection with the 

 scientific work of the Michigan Fish Commission at Charlevoix. This 

 involved a careful examination of Round Lake and Pine Lake, collections 

 in Lake Michigan and the lakes on Beaver Island, and cursory examina- 

 tions of the small lakes in the neighborhood of Charlevoix. 



