51 



subaqiiatic animals of every description: special collections of fishes and 

 other forms were accumulated for a study of the food of the species under 

 varying conditions; a(iuarium and l)reeding-cage operations were carried 

 on. especially with aquatic insects and Insect larvae for a study of life 

 histories and the determination of immature stages hitherto undescribed; 

 and critical and final microscopic studies of perishable forms (chiefly pro- 

 tozoans and rotifers) were carried forward. 



The force engaged worked from the beginning of April to October 1st 

 under unusually difficult circumstances, with perfect fidelity and great, 

 Intelligence and with tireless energy and enthusiasm. At thejlatter date 

 the cabin boat was brought in and all the station party returned to 

 Champaign except Mr. Hart, who remained two weeks longer. 



Most of the equipment remains at Havana in the laboratory rooms, 

 and regular trips will be made to the station during the fall and winter 

 at intervals of about three weeks, with parties large enough to work 

 every station thoroughly by all the methods above described. It is our in- 

 tention to ship a large part of these winter collections alive to the 

 University for study on our return from these brief trips. 



The results of this first season's work are, of course, but just begin- 

 ning to appear. Indeed, the problems to be solved in such situations 

 have scarcely more than dimly shown themselves as yet. but the promise 

 Is nevertheless already interesting. Notable contrasts in kind and num- 

 ber appear between animals of the springy shore of river or lake and 

 those of the muddy bottom only a few rods away on the other side; 

 between river and lake: between Quiver and Thompson's lakes: between 

 each of these and Matanzas lake, and between all the other lakes and 

 the temporary pond distinguished locally as Phelps lake— contrasts some- 

 times easily comprehensible, as in the first instance given, where the 

 cool spring water tiowiug in abundantly is evidently favorable to the 

 gammarids and aselli swarming there, and sometimes peculiarly puzzling, 

 like that between Quiver lake C'U the one hand, whose waters were 

 choked in midsummer with a dense growth of aquatic vegetation, but 

 contained fewer of the smaller animal forms (entomostraca and the like) 

 than the open current of the river itself, and Thompson's lake on the other 

 hand, where the water was relatively clear of aquatic plants, but abounded 

 in rotifers and entomostraca. Still more curious was the contrast 

 between the similarly situated and very similar lakes, Quiver and 

 Matanzas, the waters of one loaded and clogged with plants, and sw-arm- 

 ing with -small mollusks and insect larva^. and tliose of the other with 

 scarcely a trace of even microscopic vegetation, and with a correspond- 

 ingly insignificant quantity of animal life. 



The course of events in a body of water like Phelps lake, with its 

 terrific seasonal vicissitudes, ranging from complete overflow and loss of 

 identity to absolute drying away" in now and then an exceptional year, is 

 extremely interesting to the oecologist. The extraordinary instability of 

 the system, one predominant and excessively abundant form quickly 

 following another almost to tlie suppression of its predecessor, and all 

 finally overwhelmed in a common doom, gives to the student an im- 

 pression of an unhealthy organism, caught in the trap of an unfavorable 

 environment, and hurrying througli the stages of a fatal disease. 



One of the surprises of the season was the abundance of minute life in 

 the main stream, which, as already intimated, sometimes contained a 

 greater abundance of animal forms than most of the lakes connected 

 with it: and another was the relatively small difference between the 

 animals frequenting widely unlike situations in the same body of water. 

 This is not the place, however, for a summary of our discoveries, and I must 

 content myself with the statement that the freshness and fruitfulness of 

 the field was well illustrated by the large number of new forms found, 

 especially among rotifers, worms and insect larvie. 



