173 



EcoLO(JicAL Notes on the Mussels of Winona Lake.* 



By T. J. Headlee and James Simonton. 



In the siimuier of I'.Mt:^ the writers, under the direction of C. H. 

 Eis'enmanii. made oliservations on the mussel distribution of Winona 

 Lalve with a view to determining the reason for the same. We examined 

 the shore line from 4 inches to 4 feet by wading, from 4 to 7 with 

 a clam rake, from 7 to SO feet with an ii-on dredge. 



The species found Avere determined by comparison with shells that 

 had been named by Call. Simpson and Baker. The nomenclature is 

 that used by Call in his report on Indiana Mollusca. Geological Report, 

 1899. They were; I'nio luteolus. Unio subrostratus, TJnio glans, Unio 

 fabalis, Unio rubiginosus. Anodonta grandis, Anodonta edentula Mar- 

 garitana marginata. 



This is a deep kettle-hole lake. In general tUe beaches are composed 

 of sand and gravel, which shade off with A'arying rapidity into marly 

 sand, then into sandy marl, then into coai'se white marl, and finally into 

 the fine dark marl that covers the l)Ottom in all the deeper parts of the 

 lake and which is the accumulation of plankton tests. The bottom 

 steadily grows softer as the proportion of dark marl increases. So soft 

 does it become that a small sounding lead sinks into it of its own weight 

 from 6 to 12 Inches. In some places, especially the southwest side and 

 in the little lake the shallow part of the beach is formed of muck which 

 shades off into marl witliout the presence of any sand or gravel. 



In general it may be said that the mussel zone extends from the 

 shore line to where the bottom changes to very soft marl. This region 

 will average from 4 inches to feet of water, although in some places 

 the mud comes to within a few feet of the water's edge, while in others 

 the sandy and gravelly bottom runs out into 22 feet of water. 



A. grandis is usually found just on the outer edge of the sand 

 and gravel bank, while A. edentula appears most numerously a little' 

 farther out. A few specimens of both species were taken closer in shore, 



"Contributions from the Zoological Laboratory of Indiana University, No. 62. 



