48 



MUSSEL FAUNA OF THE KANKAKEE BASIN. 



21. Strophitiis edentulus {Say). — This is an exceedingly variable 

 shell, considerably resembling an Anodonta^ and in none of its forms 

 of any commercial importance. It is found in a great variety of 

 situations, in lakes and ponds and both in rather small creeks and 

 large rivers. It is never found in great abundance anywhere. In 

 the Kankakee Basin we found only a few, but these were widely dis- 

 tributed. A dead shell was found at the first station made, on the 

 banks of the Yellow River at Bremen. Some were found at the 

 pearler's pile below the dam at Plymouth, some in Tippecanoe Lake, 

 dwarfed and mostly dead, one valve in the old bed of the Kankakee at 

 Davis, Ind., two at Momence, one at Custer Park with distomid 

 cysts, some at Wilmington, and a gravid example in Forked Creek 

 (Aug. 27). In Mazon Creek at Gardiner, 111., occurred a brightly 

 rayed form, jyavonia. 



The question of rays appears to be closely related to clearness of 

 water; in turbid streams mussels are usually dull colored, while in 

 clear streams they are usually more brightly rayed. 



22. Ptychohranchus phaseolus {Hildreth). Kidney -shell. — This 

 species, which at its best is a very good button shell, having a white 

 nacre of soft satiny luster, was found only in Tippecanoe Lake. 

 It is also fairly common in the Tippecanoe River, but was not found 

 in the Kankakee River or any of its tributaries. 



23. Ohovaria ellipsis {Lea). Missouri niggerhead. — This is a 

 first-class button shell and well known among clammers and button 

 manufacturers. It is of rare occurrence in the Kankakee. We saw 

 it only at the clammer's shell pile at Momence. 



2.lf. Laiiipsilis alatus {Say). Pancake. — This shell, on account of 

 its thinness and purple color, is of no value to the button trade. It is 

 rare in the Kankakee. We found only one decayed dead shell above 

 Nickel Plate crossing and another dead shell at Custer Park. 



25. Lampsilis glans {Lea). — This is a shell of lakes and small 

 streams. Its small size and purple color prevent its being of any 

 commercial value. L. glans was found only at Plymouth below the 

 dam and in Tippecanoe Lake. At Plymouth it was found gravid . 

 (July 27). The glochidia were in a kidney-shaped mass in the 

 posterior part of the outer gill, and are apron-shaped in outline, as 

 is usual in Lampsilis. The edge of the gravid portion of the gill 

 has a deposition of black pigment, as in L. ventricosus and related 

 forms. 



26. Lampsilis ellipsif ormis {Conrad). — This small shell (too small 

 to be of any value commercially) was found only in the lower part 

 of the river and in the tributary streams. The first we saw were in 

 the clammer's pile at Momence, where it was fairly common. We got 

 20 there. It was also common in Forked Creek near Wilmington, 

 where all but one were gravid (Aug. 27). Shells opened by musk- 

 rats were quite common in Mazon Creek near Gardiner, 111. 



