260 POTTSVILLE FAUNA OF OHIO 



Subgenus Hemizyga Girty 

 Hemizyga n. sp. 

 PL XV, fig. 25 



Description. A small gastropod from the Lower Mercer limestone 

 at Bald Knob, Licking County, represents in all probability a new 

 'species of Hemizyga, but unfortunately an adequate description or 

 figure cannot be made on account of the imperfection of the only known 

 specimen. The form is preserved as an external mold with the three 

 lower volutions almost complete and the remainder of the spire so 

 indicated that the height can be fairly accurately observed. The 

 following description, although incomplete, shows the features of the 

 shell which can be noted: 



Shell small, robust, conical, composed probably of about seven 

 volutions; spire median in height; volutions enlarging rapidly in size, 

 convex, and apparently regularly rounded; body whorl forming almost 

 one-half the length of the spire; sutures well defined. Surface marked 

 by numerous sharply elevated, longitudinal ridges about twenty-four 

 of which occupy a single volution, crossed by fine, regular, closely 

 arranged revolving lines which are sharply defined on the lower half 

 of the whorls, but become less distinct on the upper half. 



Dimensions. Length of shell 10 mm., height of body whorl 4.5 mm., 

 width 6 mm. (not the width of the entire shell, but only of the portion 

 preserved). 



Horizon and locality. Lower Mercer limestone: Licking County, 

 Bald Knob, Locality 46, r. 



Genus Bulimorpha Whitfield 

 Bulimorpha inornata (Meek and Worthen) ? 



1860 Loxonema inornata. Meek and Worthen, Proc. Acad. Nat. Sci. Phil., p. 465. 

 Upper Coal Measures: Springfield, Illinois. 



Remarks. Several small specimens from the Lower Mercer and 

 McArthur limestones have been doubtfully referred to Bulimorpha 

 inornata to which they seem closely related. However, as their con- 

 dition of preservation is poor and as B. inornata has been described 

 from a much higher horizon in the Coal Measures, our form may not 

 represent the same species. A single individual from the Upper Mercer 

 member, only 5 mm. in height, also seems closely related to B. inornata 

 although its size is much less. 



Horizon and locality. Lower Mercer limestone: Perry County, 

 Locality 35, r; Licking County, Locality 48, r; Stark County, Locality 



