Lake Maxinkuckee, Physical and Biological Survey 43 



on each side by a flat sedgy plain which indicates the former 

 breadth and importance of the stream. The colonization of the 

 lake with mussels was probably effected chiefly during the period 

 when the Outlet was a broad and relatively important stream. 

 The situation has been carefully considered and seems to show that 

 the mussels of the river and lake are isolated from each other and 

 that there is no longer any vital connection between them. The 

 strongest indication of the independence of the lake and river 

 mussel faunas is the appearance of the Maxinkuckee mussels them- 

 selves; these are lake-mussels, easily distinguished for the most 

 part from river mussels of the same species, and many of them are 

 ditinguishable also from the mussels of the neighboring lakes. 



The Tippecanoe River is fairly well supplied with mussels. Al- 

 though the number of species is considerably fewer, and the size 

 of the individuals is generally smaller, than that of the Wabash 

 into which it flows, it compares very favorably with rivers of its 

 size. At Delong, Ind., a short distance above the mouth of the 

 Outlet of Lake Maxinkuckee, were obtained in one bed specimens 

 representing 24 species of mussels or about twice the number of 

 kinds found in Lake Maxinkuckee. 



Our knowledge of the extent and importance of migrations of 

 fishes from the Tippecanoe River up to the lake and from the lake 

 down to the river — a question which has a marked bearing upon 

 the relationship of the mussel faunas — is not as complete as it 

 should be, but indications are that they are not important or ex- 

 tensive. Inasmuch as the geographic distribution of a given 

 species of mussel is coextensive with that of the species of fish 

 which serves as its host, this question is worthy of careful consider- 

 ation. There are several species of fishes of the Tippecanoe River 

 (Etheostoma camurum, Hadropterus evides, Hybopsis amblops, 

 etc.) which were not found either in the Outlet or in the lakes, and 

 other species {Hadropterus aspro, Ericymba buccata, Diplesion 

 blennioides) which have pushed halfway up the Outlet, but were 

 found no further up. 



In this connection, the mussel fauna of the Outlet is worthy of 

 consideration, and on various occasions, but especially on a trip 

 down the Outlet September 30, 1907, particular attention was paid 

 to this feature. 



The Outlet is not particularly well suited to the life and growth 

 of mussels ; the bottom is either a firm peaty soil or fine shifting 

 sand ; moreover, the course has been artificially changed in some 

 places and the stream has naturally shortened its length in others 

 by making cutoffs. In addition to this the mussel fauna of such 



