202 Natural History Bulletin. 



specimens from all of the states from Nebraska to Canada 



show considerable variation in size, within the extremes of 



which the few fossils which were examined would easily fall. 



This species occurs at present throughout the United States. 



Zonites radiaiiihis^ Alder. Not common. Fossils from 

 Johnson count}-, Iowa, and Lancaster county, Nebraska were 

 compared with recent shells from Iowa, Illinois and Nebraska. 

 The latter are somewhat variable, the range of variation 

 covering the fossils. At present this species is circumpolar 

 in its distribution, and extends southward to the Gulf of 

 Mexico. 



Zonites viinusciilns (Binn.) Fisch. and Cr. Rather rare. 

 Fossils from Johnson county, Iowa, and Lancaster county, 

 Nebraska, were studied. Owing to the scarcity and condition 

 of the fossil material satisfactory comparisons could not be 

 made. 



Distributed at present throughout the United States. 



Zonites limatithis, (Ward) Binn. Common. Fossils from 

 Johnson county, Iowa, and Cuming, Saunders, and Lancaster 

 counties, Nebraska were compared with recent specimens 

 from Indiana and Illinois. The fossils, which show but little 

 variation, are uniformly larger than any recent shells observed 

 by the writer, and exceed the dimensions given by Binney. 



The present range of typical Z. liinatiihis is from New 

 York to California, and northward. 



Zonites fulvtis^ (Drap.) Binn. Quite common. Fossils 

 from Johnson, Polk and Pottawattamie counties, Iowa; and 

 Cuming, Saunders, and Lancaster counties, Nebraska were 

 compared with recent shells from Montana, Nebraska, Iowa, 

 Illinois, Ohio, and New York. The fossils average larger 

 than the recent shells, the Montana specimens alone equalling 

 them in size. 



A circumpolar species, occuring now throughout the United 

 States. 



