Occasional Papers of the Museum of Zoology 9 



Buconulus sp. ? 



Helicod'iscus paralhius (Sayj. 

 Piinctuni pygiiKUHin (Dr.). 

 Strobilops sp. ? 

 Pupoides marginata (Say). 

 Bifidaria armifera (Say). 

 Bifidaria contracta (Say). 

 Bifidaria cristata P. & V. 

 Bifidaria hordeacella Pil. 

 Bifidaria pentodon (Say). 

 Bifidaria procera (Gld.). 



21. Red Rock Creek, near Billings, Xoble Co., Oklahoma. 

 Land species identified by Clapp ; Muscuiiitm by Sterki. 



Zonitoidcs minuscula (Binn.). 

 Zonitoides singleyana Pils. 

 Zonitoidcs miuimus \ an. 

 Euconulus sp. ? 

 Vallonia costata (Milll.). 

 Helicodiscus parallelus (Say). 

 Pupoides marginata (Say). 

 Bifidaria armifera (Say). 

 Bifidaria contracta (Say). 

 Bifidaria holzingeri St. 

 Bifidaria pentodon (Say). 

 Bifidaria procera (Gld.). 

 Bifidaria tappaniana (C. B. Ads.). 

 Planorbis Icntus Say var. ? 



Musculium sp. ? "Two, nepionic and very young at 

 that, probably transT'crsum." ( Sterki") . 



22. Creek, fifteen miles east of Chicasha, Oklahoma. 

 Land species identified by Clapp. 



Zonitcidcs arborca (Sav)? 



