MUSSEL FAUNA OF THE KANKAKEE BASIN, 49 



27. Lampsilis iris {Lea). — This very pretty shell is of no com- 

 mercial importance on account of its small size. It was fairly com- 

 mon and reached an unusual size in the stretch of Yellow River from 

 Plymouth to below Burr Oak. Two were obtained in Tippecanoe 

 liake, one of them gravid (July 28). A gravid one was obtained 

 above Zinc Bridge (Aug. 3). One was found dead in the Kankakee 

 at Davis, Ind. 



28. Lampsilis suhrostratus {Say). — This shell, like L. ins., which 

 it in some respects resembles, is too small to have any commercial 

 value. Although occasionally occurring in rivers, it is essentially a 

 lake or slough shell. All we obtained within the Kankakee Basin 

 were found in lakes. Four were obtained in Twin Lakes (July 2), 

 of which one was gravid, the young being contained in a kidney or 

 bean shaped mass in the posterior part of the outer gill, the mass 

 being deeply ribbed, dusky near the margin, and white along the very 

 margin. Some were obtained in Tippecanoe Lake and some in Fish 

 Lake, where it was fairly common. Fragments were found at Eound 

 Lake, a small lake near Knox, Ind. 



29. Lamjysilis rectus {Lamai'ck). Black sand-shell. — This species, 

 when it has white nacre, as it sometimes does, is an excellent shell for 

 both buttons and knife handles, approaching in value the yellow sand 

 shell. In some rivers the majority of shells are white, in others 

 colored. This shell is rare in Yellow River. Some were found at 

 the pearler's pile below the dam at Plymouth, Ind., and in 1906 a few 

 were found at Knox. A few were found also in the Kankakee above 

 Nickel Plate crossing, some at Davis, and near Kouts and Hebron 

 Bridge. It was not cormnon in the clammer's pile at Momence, and 

 some young shells were found at Wilmington. It was also in the 

 Iroquois at L'Erable and at the mouth. 



The shells of the upper portion of the Kankakee were all colored, 

 some of them a deep purple. Lower down this color faded to a 

 pink. In a pearler's pile at Momence we found the first white-nacred 

 one. The color of this shell seems to be about the same as that of U. 

 ffibhomis and seems to respond to the same conditions. It is not, how- 

 ever, distributed the same in the shell, but seems to be most marked 

 in the umbonal cavity or teeth. Shells of L. rectus which are per- 

 fectly white otherwise often are pink or amethystine purple on the 

 teeth or umbonal cavity. The rosy hue of Q. coccinea seems to be 

 of a somewhat different nature and notably differs as one proceeds 

 down the river. 



30. Lampsilis fallaciosus {Smith). Slough sand-shell. — This spe- 

 cies, valuable for small buttons, is rare in the Kankakee Basin. The 

 only ones found were in the Iroquois River at L'Erable. Most of 

 these contained distomid cysts in the margin of the mantle. 



31. Lampsilis Ugamentinus {Lamarck). Mucket. — The mucket is 

 one of the best known of the button shells, and probably more tons of 



