182 POTTSVILLE FAUNA OF OHIO 



mens of P. morrowensis Mather, borrowed for this purpose from the 

 Walker Museum at the University of Chicago, and with one exception 

 no essential differences could be noted between the two forms. How- 

 ever, indications of the double row of spines on the cardinal slopes and 

 the main flanks which characterizes the Morrow species, was noted on 

 only one of the Ohio specimens although a considerable amount of ma- 

 terial was examined. It seems probable that this form represents an 

 individual variation, rather than that the spines were originally present 

 on all of the specimens but failed to be preserved. There appears to 

 be a gradual gradation between this form and P. semireticulatus an$ 

 for the present it seems advisable to refer to it as a variety of the latter 

 species. 



Horizon and locality. Boggs member: Muskingum County, Lo- 

 calities 26, 27, 28, c. Lower Mercer member: Scioto County, Locality 

 31, c. Upper Mercer member: Perry County, Locality 63, c; Mus- 

 kingum County, Localities 29, 38, c. 



Genus Pustula Thomas 

 Pustula nebraskensis (Owen) 



1852 Productus nebraskensis. Owen, Geol. Rep. Wisconsin, Iowa, and Minnesota, 

 p. 594, Tab. 5, Fig. 3. 

 Carboniferous limestone: Bellevue, Missouri River, Nebraska. 



Remarks. This common Pennsylvanian fossil occurs abundantly 

 in rocks of Pottsville age in Ohio, and is one of the most widely dis- 

 tributed forms. Although it characterizes the marine limestone hori- 

 zons, it has not been found below the Lowellville member. Much of 

 the material in the collections studied is in an excellent state of pres- 

 ervation. 



Horizon and locality. Lowellville limestone: Muskingum County, 

 Locality 19, r; Mahoning County, Locality 22, r. Widely distributed 

 in the Boggs, c, Lower Mercer, Upper Mercer, McArthur, aa, and 

 Black Flint, a, members. 



Pustula pertenuis (Meek) 

 PL VIII, fig. 8 



1866 Productus cancrini. Geinitz (non de Verneuil), Die Garb, und Dyas in Nebraska, 

 p. 54, PI. 4, Fig. 6. 

 Nebraska City, Nebraska. 



1872 Productus pertenuis. Meek, U. S. Geol. Surv. Nebr., p. 164, PI. 1, Fig. 14; 

 PI. 8, Fig. 9. 



Upper Coal Measures: Nebraska City and Brown ville, Nebraska; Grass- 

 hopper Creek, Kansas. 



