MUSSEL FAUNA OF THE KANKAKEE BASIN. 



51 



3^. Lampsilis ventricosiis (Barfies). Pockethook. — Lampsilis ven- 

 tHcosus is a widely distributed and exceedingly variable shell, occur- 

 ring in both lakes and streams. Its commercial value varies greatly 

 in different situations. In some locations it is too thin to be of any 

 value whatever. The nacre is usually white and of good luster, 

 though pink or reddish ones are occasionally found. 



In the Yellow and Kankakee Rivers this species reaches unusual 

 size and thickness; indeed, in 1906 was obtained, in the Yellow River 

 near Plymouth, what at that time was the record shell for this species, 

 exceeding in size any in the National Museum collection. In the 

 active collecting that has been going on since, it is possible, of course, 

 that larger shells have been found. It was^^airly abundant in the 

 Yellow River below Plymouth and became more common in the 

 Kankakee, until below Burton's camp it was present at every station. 

 We did not find it in the Iroquois or in any of the lakes within the 

 Kankakee Basin, though it is fairly common in Lake Maxinkuckee. 

 The form found in the Yellow and Kankakee is the large oval form, 

 either plain or, in some cases, beautifully rayed (occidens) ; near 

 the city of Kankakee, 111., however, we obtained some specimens with 

 a pretty well-marked posterior ridge {suhovatus). It was repre- 

 sented by numerous large shells in the clammer's camp at Momence. 

 They were found becoming gravid at Plymouth July 15, spawning in 

 the Tippecanoe River July 28, gravid at Zinc Bridge August 4, and 

 at Custer Park August 27. In Yellow River this species bears numer- 

 ous small dorsal baroques. 



SS. Micromya f abate {Lea) . — This dainty little shell was found at 

 Tippecanoe Lake and is fairly common in the Tippecanoe River, but 

 was not found in the Kankakee Basin. It has no commercial value. 



36. Truncilla sulcata {Lea). — This little shell was found at Tippe- 

 canoe Lake, but was absent from the Kankakee Basin. It is interest- 

 ing as the representative of the most highly differentiated genus of 

 mussels, a genus mostly southern in distribution. It has no commer- 

 cial value. 



ECONOMIC CONSIDERATIONS. 



Although the upper portion of the Yellow River is fairly w^ell 

 populated with mussels, it is a small stream and the distance is 

 short, so that commerical operations would soon deplete it. It is, 

 however, a region of especially large and fine L. ventricosus. Many 

 of the finest shells of this part of the river have been killed by pearl- 

 ers, and to gather up and market the cleaned shells might be worth 

 while to some resident of the vicinity. It would hardly be profitable 

 for a professional clammer to construct gear and work this region. 

 Whether it would be a good plan to procure spawn of the remarkably 

 fine ventricosus found here for planting elsewhere can not be deter- 



