57 



Siiccinea calumetensis Calkins. Calumet Marshes, Chicago. 



" peoriensis Wolf. Peoria. 



" ittinoisensis Wolf. Canton. 

 Polygyra muttilineala algonquinensis Nason. Algonquin. 



Of the above list the following are now considered syno- 

 nyms of other species: 



Unio upsoni = Lampsilis ligamentina Lamarck. 

 Goniobasis grosvenorii = Goniobasis semicarinata Say. 

 Physa elongata = Aplexa hypnorum Linne. 

 Lymnsea ferrisdi = Lymnsea caperata Say. 



" 8ufflatu8 = Lymnsea palustris Miiller. 

 Zonites upsoni = Vertigo ovata Say. 

 Suceinea calumetensis — Succinea retusa Lea. 



Illinois lies wholly within Binney's Interior Region of the 

 Eastern Province. Of the 69 species mentioned by Binney as 

 inhabiting this region, all but 8 have been found in Illinois. It 

 will thus be seen that the Illinois molluscan fauna is typical 

 of the interior region. Among the land shells the families 

 Zonitidw and Helicidce are represented by the largest number 

 of species; among the genera, Polygyra is the most noteworthy. 



The Mississippi Valley is the metropolis of the pearly fresh- 

 water mussels (Unionidce), and the position of the state, bor- 

 dered on the west by the Mississippi River and on the south and 

 east by the Ohio and Wabash rivers, has produced a large and 

 varied Unio fauna, no less than 98 species and varieties being 

 found in the various rivers and lakes. The Sphceriidw, Vivi- 

 paridce, Amnicolidce, and Lymna?ida? are also notably developed. 



The fiuviatile species are distributed among 9 families and 

 47 genera. Of these, 2 families and 25 genera are bivalves, '5 

 families and 7 genera are pulmoniferous, and 4 families and 15 

 genera are branchiferous and operculate, as is evident from the 

 following list. 



FLUVIATILE MOLLU8KS. 



„ ., ,r, No. of No. of 



Family. Genus. Species. Varietl. 



Unionidas Truncilln 6 1 



Lampsilis 24 



Micromya 1 



Obovaria 4 



