70 



Lake Ma.vinkackee, Physical and Biological Sarrcii 



cal specimens to Mr. Bryant Walker of Detroit, Mich., who identi- 

 fied the shells with a few coarse straight undulations on the beaks 

 as Lampsilis ventricosa canadensis and the others as L. luteola. 



The Maxinkuckee specimens were also compared with L. ventri- 

 cosa from Lake Champlain, and were found to be much like them. 

 The Champlain examples which were free from staining of the 

 epidermis more closely resembled in color the ventricosa of the 

 rivers. 



The specimens of L. ventricosa differed considerably in the dif- 

 ferent beds. Lost Lake examples are usually rather small, and are 

 stained a peculiar ashy-gray. Those from the near Farrar's are 

 mostly small and apparently young and are rather well rayed; 

 they resemble river forms more closely than any others in the lake. 



The large oval L. ventricosa of Long Point are the heaviest 

 shells of the lake. A peculiarity of several of these shells is a 

 conspicuous rib-like thickening on the inside, extending from near 

 the umbonal cavity postero-ventrally. The nacre is soft satiny in 

 luster, and not very iridescent. This oval form of ventricosa 

 found at Long Point furnishes the only shell in the lake that could 

 be used to any advantage in the manufacture of buttons, and even 

 it produces rather inferior material. Some of these shells were 

 sent to a button factory at Davenport and buttons were made of 

 them. The following is a set of measurements of these large 

 shells: 



Although the reproductive phase of L. ventricosa of the lake 

 is much less conspicuous than in the river mussels, most of them 

 apparently succeed in reproducing themselves. Most of the fe- 

 males found later in autumn have more or less numerous glochidia 

 in the gills. No infected fishes or very young mussels of this spe- 

 cies were seen. 



The most common parasite is Atax, and it is not particularly 

 abundant. Of six examples collected near Farrar's July 24, 1909, 



