116 



OHIO FOSSILS 



we have used them although we strongly suspect that some of them should be changed. Work 

 in progress, but not as yet published, will bring these names up to date. The commoner forms 

 may be identified by means of the following key. 



Key to the Commoner Pennsylvanian Gastropods of Ohio 

 (see p. 4 for use of keys) 



1. 



a) 





b) 



2. 



a) 





b) 



3. 



a) 





b) 



4. 



a) 





b) 



5. 



a) 





b) 



6. 



a) 





b) 



7. 



a) 





b) 





c) 



8. 



a) 





b) 



9. 



a) 





b) 



10. 



a) 





b) 



11. 



a) 





b) 



12. 



a) 





b) 



13. 



a) 





b) 



Spire longer than the body whorl 6 



Spire shorter than the body whorl 2 



Spire sunken below level of last whorl 3 



Spire low but above level of last whorl Worthenia 



Umbilicus closed, spire entirely hidden by last whorl 4 



Umbilicus open, spire visible Schizostoma 



Axial ornamentation stronger than spiral ornamentation .... Pharkidonotus 

 Spiral ornamentation stronger than axial ornamentation 5 



Axial ridges almost equal in size Euphemites 



Axial ridges of 2 sizes, one large separated by 3 to 5 



smaller ones Patellostium 



Height more than 3 times the width 7 



Height less than 3 times the width 10 



Ornamentation of axial ridges only Loxonema 



Ornamentation of spiral ridges only 8 



Ornamentation of axial and spiral ridges 9 



Three widely spaced spiral ridges only Orthonema 



Four or more closely spaced spiral ridges Aclisina 



Spiral ridges numerous, covering entire whorl Aclisina 



Two spiral ridges only, near the top of the whorl. . . . Orthonema bilineatum 



Spire shorter than the aperture 11 



Spire and aperture almost equal in length 13 



Spire sharply pointed Sphaerodoma 



Spire bluntly pointed 12 



Axial ridges fine, crinkled Phanerotrema 



Axial ridges fine, straight Bulimorpha 



Shell with strong spiral ridges Pleurotomaria 



Shell without spiral ridges Soleniscus 



