Lake Maxinkuckee, Physical and Biological Survey 61 



inner surface of the shell. The rest periods are distinct black 

 lines, often plainly visible through the translucent shell when held 

 up to the light. Rays are always invisible by reflected light in 

 the lake shells, but in some examples they were visible by trans- 

 mitted light. The animal has orange-colored flesh. The few liv- 

 ing examples examined indicate that parasites are common: one 

 contained three old Atax ypsilophorus, and several young. 



One gravid example was found, October 17, 1907. The young- 

 est example found was 42 mm. long and exhibited four rest periods. 



8. LAMPSILIS GLANS (Lea) 



Fairly common in the main lake ; dead shells are often found 

 along shore, and occasionally the living mussels are to be seen in 

 shallow water at the various mussel beds in the lake. It is quite 

 abundant along the edges of the thoroughfare joining the lakes, 

 and is common in Lost Lake. The examples found in the thorough- 

 fare and Lost Lake were of unusually large size ; this is one of the 

 few species of mussels which are as large or larger in the lake than 

 in the neighboring rivers. L. glans appears to prefer shallow water 

 along shore. A good number of shells recently cleaned out by 

 muskrats was found near the water's edge at Long Point in the 

 late autumn of 1913. 



In the Tippecanoe River at Delong this was a very abundant 

 species in the greasy whitish blue clay along shore, and was here 

 one of the favorite morsels of the muskrat. With the exception 

 of Micromya fabalis this is the smallest species of mussel found 

 in the lake. It can be easily recognized by its black epidermis, 

 small size and purple nacre. 



9. RAINBOW-SHELL 



LAMPSILIS IRIS (Lea) 



Rather common in the lake in shallow water near shore, found 

 scattered among the other species in the various shell-beds. There 

 is a good colony in the Lost Lake bed, and it is fairly abundant 

 off the depot grounds, by Kruetzberger's pier, at Long Point, and 

 at the bed near the mouth of Norris Inlet. 



The lake shells differ markedly from those of the neighboring 

 rivers, so much so that it is easy to separate the lake and river 

 shells at a glance. The lake shells are considerably more elongate, 

 and the epidermis is stained a deep brown, mostly concealing the 

 rays ; when these are visible they are brownish rather than green, 

 and the umbones are rather eroded. The shells, indeed, resemble 



